235 F.3d 687 (1st Cir. 2000)
JACK SHEEK, Plaintiff, Appellee,v.ASIA BADGER, INC., Defendant, Appellant.
Nos. 99-2221,  00-1116.
United States Court of Appeals, For the First Circuit.
Heard Oct. 6, 2000.Decided December 29, 2000.

APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF MASSACHUSETTS. Hon. Reginald C. Lindsay, U.S. District Judge.[Copyrighted Material Omitted]
William A. Zucker, with whom Risa G. Sorkin and Gadsby Hannah LLP,  were on brief, for appellant.
Dana A. Curhan, with whom Kenneth Levine, Ross Annenberg and Annenberg and Levine, were on brief, for appellee.
Before Torruella, Chief Judge, Bownes, Senior Circuit Judge, and Boudin, Circuit Judge.
TORRUELLA, Chief Judge.


1
On March 9, 1994, plaintiff-appellee  Jack Sheek, while working as an employee of Mobil Oil Singapore Private  Ltd. ("Mobil") in Jurong, Singapore, slipped on a small pipe and  injured his shoulder.  Sheek brought suit in  United States district  court against defendant-appellant Asia Badger, Inc. ("Asia Badger"),  alleging that Asia Badger or one of its subcontractors performed  certain repiping work and negligently failed to correct a known  hazardous condition which proximately caused him serious injuries.  A  jury found in favor of Sheek and awarded him $387,000.  Asia Badger  appeals, arguing that the district court committed reversible error by:  (1) making erroneous evidentiary rulings; (2) giving the jury confusing  and misleading jury instructions; and (3) denying Asia Badger's post-verdict motions for judgment notwithstanding the verdict and a new  trial.


2
For the reasons set forth below, we affirm the district court  on all issues.

I.  BACKGROUND

3
The basic facts of the case may be summarized as follows.

A.  The Project

4
In June 1992, Sheek went to Jurong, Singapore to work as an  operations specialist on a new aromatics plant under construction by  Mobil (the "Project").  Asia Badger, a wholly-owned subsidiary of  Badger Engineering, Inc., was the general contractor on the Project. During the Project's early stages, Sheek worked during the day and was  responsible for walking through the plant and reporting on the work  being done by Asia Badger.  Part of his report included operational  problems, or "punch list" items, that needed to be corrected.  Sheek  referred these items, directly or through intermediaries, to Asia  Badger.  In turn, Asia Badger or its subcontractors worked on the  identified problems.


5
In January 1994, Sheek became the night superintendent and  began working twelve-hour shifts from 6:00 p.m. to 6:00 a.m.   Sheek  ran equipment, flushed pipes, and completed other start-up tasks in  order to prepare the plant for operation.  Sheek also continued to  identify punch list items which were passed on to the day shift. These  items were addressed during the day, and Sheek checked the progress of  the work while on duty at night.


6
In mid-January or early February 1994, Mobil discovered that  four xylene splitter pumps were operating at excessively high  temperatures.  Tests indicated that the piping was too small,  preventing cooling water from adequately circulating through the pumps. Sheek received orders to take these pumps out of service so that work  could be performed on them during the day shift.  The pumps required  two types of work.  The first was maintenance work, such as the  replacement of seals and bearings damaged by the lack of coolant: this  involved unscrewing a flange, removing piping, replacing the parts, and  screwing the piping back together.  The second type of work involved  repairing the actual design defect, i.e., cutting out the inadequate  cooling pipes and replacing them with larger diameter piping.  Like  other punch list items, Sheek noted the work completed on the pumps  when he arrived on duty in the evening.

B.  Sheek's Accident

7
When the facility entered its final stages of construction  in early 1994, Mobil gradually took control of sections of the plant as  they became operational and expanded its maintenance work in those  areas.  Full mechanical acceptance of the plant by Mobil occurred on  March 1, 1994.  One week later, on Marcha8, Mobil held a dedication  ceremony for the plant.  In preparation, some areas of the plant were  shut down and cleaned.


8
Also on March 8, Sheek received instructions to take the last  of the four pumps, the "D" pump, out of service.  On the evening of  March 9, Sheek observed that some of the piping in the D pump had been  changed to a larger diameter size.  At 11:00 p.m. that same evening,  Mobil workers arrived with a large control valve which had been removed  during the day for maintenance.  Sheek checked up on the workers  several times as they reinstalled the valve.  At about 3:00 a.m. on  March 10, Sheek walked past the xylene splitter pumps on his way to  look at the valve once more, since the work was nearing completion.  As  Sheek neared the D pump, he stepped on a piece of pipe, fell backwards,  threw his right arm behind him and grasped a drain line to break his  fall.   As he got up, Sheek saw the pipe, removed it from the walkway  and continued with his shift.

C.  Injury and Treatment

9
When Sheek awoke the next morning, he felt pain in his right  shoulder and could not raise his arm. On March 12, Sheek saw Dr. Jimmy  Darwulla, an orthopedic surgeon in Singapore.  Dr.aDarwulla determined  that Sheek had a partial tear in his right shoulder muscle and  prescribed medication and physical therapy.  That same day, Sheek filed  an accident report with Mobil, identifying the pipe he slipped on as  the kind being replaced on the xylene splitter pumps.  On March 18,  Sheek returned to his home in Texas to obtain a visa for a three-week  assignment with Mobil in Saudi Arabia, which had been arranged prior to  his accident.  Although Dr. Darwulla had advised Sheek that he was not  fit to go on the assignment, Sheek left for Saudi Arabia shortly  thereafter.


10
After returning from his assignment in Saudi Arabia, Sheek  visited Dr. Reid, an orthopedic surgeon in Texas.  Dr. Reid diagnosed  a complete tear in Sheek's rotator cuff and recommended surgery, which  was performed in June 1994.  Sheek underwent a second surgery several  weeks later to remove bone spurs and scar tissue that was causing him  pain.  Following the surgery, Sheek accepted a temporary assignment  with Mobil but was unable to obtain a full medical release and thus  return to work permanently.  Sheek declined Mobil's offer to place him  on half pay and retired in 1995.

D.  Trial

11
Sheek filed suit against Asia Badger in the district court  for the Eastern District of Texas on June 1, 1995.  On September 5,  1996, the case was transferred to the District of Massachusetts. During the nine-day trial, both parties presented conflicting testimony  concerning almost every fact in the case.  For purposes of this appeal,  we will briefly highlight the evidence relating to three main issues:  (i) who replaced the piping work on the xylene splitter pumps; (ii)  whether Asia Badger exercised control over the persons who performed  the work; and (iii) whether Sheek's injuries were caused by the pipe on  which he slipped.

1.  The Piping Replacement

12
Asia Badger's central defense was that it was not responsible  for the repiping work performed on the pumps.  To support this  contention, Asia Badger presented the deposition testimony of Gary  Steinmetz, who worked as a mechanical engineer for Asia Badger during  the Project.  According to Steinmetz, the problem with the xylene pumps  was a result of a manufacturing error.  Specifically, in addition to  the inadequate piping, the coolers were grossly undersized and had to  be replaced with larger capacity coolers.  The piping could not be  replaced until the coolers were replaced.  Steinmetz testified that  Mobil was the only party with the proper equipment to change the  piping: Asia Badger did not work with galvanized schedule 40 pipe,  identified by Sheek as the type of pipe on which he slipped.  The  deposition of Ch Tai, Mobil's venture manager for the Project,  supported Steinmetz's testimony by revealing that Mobil had received  and replaced both the cooler and piping system in August 1994.


13
Sheek did not dispute that Mobil changed the coolers and  piping in August.  He added, however, that a different set of pipes  were also changed in March by Asia Badger.  Sheek testified that in  addition to observing some replaced pipes on the evening of Marcha9, he  had seen a memorandum prepared by Asia Badger indicating that the pipes  would be replaced and the design drawings altered accordingly to  reflect the change.  According to Sheek, moreover, the overheating of  the pumps was a result of a design problem.  During the period Sheek  worked on the night shift, Mobil only performed maintenance work on the  xylene pumps.  James Syar, a supervisor on the Project at the time of  Sheek's accident, also testified that while Mobil replaced seals on the  pumps, Asia Badger took responsibility for the pipe replacement  beginning in January or February 1994.  Syar also witnessed the  accident and identified the pipe that Sheek fell on as the same type  being replaced on the xylene splitter pumps.

2.  Control Over the Work Performed

14
Asia Badger also rejected the notion that it had control over  any persons who had allegedly completed the claimed work on the pumps  in March 1994.  To this end, the testimony of Mark Henderson, a project  control manager, indicated that after full mechanical acceptance on  March 1, 1994, control and custody passed to Mobil.  Any remaining work  was conducted by Mobil or by Asia Badger subcontractors under Mobil's  supervision.  Gary Steinmetz also testified that by this time, all but  thirteen Asia Badger personnel had left the site.


15
Sheek, however, countered this theory by testifying that  during his day duty in late 1993, he observed Asia Badger workers --  identified by their hats bearing the company's logo -- directing work  being done on the plant.  Although Sheek himself could not see the  actual work performed on the pumps once he assumed the role of night  superintendent, he stated that Asia Badger was responsible for all  punch list work that involved design defects.  Finally, Sheek's closing  statement referred to the testimony of Gary Steinmetz, who had stated  that Asia Badger's pattern of work was the same both before and after  January 1994.

3.  The Cause of Sheek's Injury

16
Asia Badger presented Dr. Kennedy, an orthopedic surgeon, to  render his expert opinion concerning Sheek's injury.  Dr.aKennedy  examined Sheek on March 18, 1997 and April 22, 1999 and his two medical  reports were admitted as exhibits.  During direct examination, he  testified that he had also reviewed the evaluation of Dr. Haig, an  orthopedic surgeon in Port Arthur, Texas, who had evaluated Sheek's  condition on October 26, 1995 as part of a disability rating for the  Texas workers' compensation system.  Dr.aKennedy then read from a  portion of Dr. Haig's report which described Sheek's alleged activities  in Saudi Arabia, including that "he had to do a great deal of heavy  work, climbing, pushing, pulling, et cetera, for about 40 days."  Dr.  Kennedy identified this report as the source of information about  Sheek's activities in Saudi Arabia.


17
On cross-examination, Dr. Kennedy offered the opinion that  the progression of Sheek's partial tear into a massive evulsion of the  rotator cuff could be explained by Sheek's work in Saudi Arabia.  Upon  further questioning, Dr. Kennedy acknowledged that he had reviewed Dr.  Haig's report since preparing his own April 1999 report.  At this  point, the court held a voir dire, during which Dr. Kennedy testified  that he had read Dr. Haig's report three weeks prior to trial.  He also  indicated that his opinion concerning Sheek's worsening injury was  based, in part, on Dr. Haig's report.

E.  Jury Instructions and Verdict

18
Both parties agreed that Singapore law governed the issues  of both direct and vicarious liability.  With respect to the latter,  the district court instructed the jury as follows:


19
The contractor is also liable for the failure  of any of his subcontractors to use such  reasonable care if the contractor exercised  direct supervision and control over the manner in  which the subcontractor does this work.  Thus, in  this case, to prevail, Mr. Sheek must first  establish that Asia Badger or one or more of its  employees was negligent or that there was  negligence on the part of an Asia Badger  contractor, and that Asia Badger exercised direct  supervision and control in the manner in which  this subcontractor performed his work.


20
With respect to the concept of Asia Badger's  direct control and supervision over the manner in  which the subcontractor performed the work  assigned to the subcontractor, I instruct you  that direct supervision and control in this  context means more than retention of general  [sic] Asia Badger to watch over the progress of  the work of the subcontractor.  It means that  Asia Badger must have exercised direct control,  not only over what work was to be done, but the  actual performance of the subcontractor as well.


21
In addition, the special verdict form submitted to the jury contained  the following question concerning negligence: "Were employees or agents  of the defendant, Asia Badger, negligent in performing the work in the  area of the alleged incident?"  The court denied Asia Badger's request  to modify both the instructions and the verdict form.


22
During its deliberations, the jury sent the court a note  asking, "Regarding Number 3 on the Verdict Form, is Mr. Sheek's  negligence restricted to the time of the accident or could it include  the subsequent recovery period?"1  The court answered the jury:


23
I have instructed you that you are to  determine whether in the first instance,  negligence on the part of employees or agents as  I described, as I defined agents, caused the  injury to Mr. Sheek, and if you determine that it  did, that is to say that negligence was the  proximate cause of injury to Mr.aSheek, then you  are to determine whether negligence on the part  of Mr. Sheek was a proximate cause of his injury.


24
The underlying question in the analysis is of  course what is the injury.


25
And depending on how you determine, what you  determine the nature of the injury to be that Mr.  Sheek has is how you answer that question.  So my  answer to you in short will be, it depends.  It  depends on what you say the injury is, whether  you consider the time -- the time of the accident  or you consider some later period.


26
After additional deliberation, the jury returned a verdict for Sheek in  the amount of $430,000, reduced by ten percent, or $43,000, based on  its finding that Sheek was also negligent.  The court entered judgment  on September 8, 1999.  On September 17, Asia Badger moved for judgment  notwithstanding the verdict and for new trial and remittitur.  The  district court denied both motions, and this timely appeal followed.

II.  DISCUSSION

27
Asia Badger challenges the jury's verdict on three grounds. First, Asia Badger contends that various evidentiary rulings prejudiced  its case against appellee.  Next, Asia Badger asserts that the district  court failed to properly instruct the jury on the requirements for  vicarious liability under Singapore law. Finally, Asia Badger  challenges the sufficiency of the evidence underlying the verdict.  We  address each of these claimed errors in turn.

A.  Evidentiary Issues

28
Asia Badger claims that the district court erred in excluding  critical portions of Asia Badger's expert testimony.  Asia Badger also  contends that the court improperly allowed Sheek and Syar to offer  testimony about which they had no personal knowledge.  We disagree.

1.  Dr. Kennedy's Testimony

29
At trial, the district court excluded portions of testimony  from Asia Badger's medical expert, Dr. Kennedy, for failure to  supplement his medical report to include changes in his medical opinion  as required by Fed. R. Civ. P. 26(e)(1).  The court noted that neither  of Dr. Kennedy's own reports linked the development of Sheek's massive  rotator cuff evulsion to his work in Saudi Arabia, and that  consequently, his opinion as to the cause of Sheek's injury was  inadmissable.  We will reverse a trial court's decision to admit or  exclude expert testimony only when there is an abuse of discretion. Coastal Fuels of Puerto Rico, Inc. v. Caribbean Petroleum Corp., 175  F.3d 18, 34 (1st Cir. 1999); Licciardi v. TIG Ins. Group, 140 F.3d 357,  362-63 (1st Cir. 1998).


30
Fed. R. Civ. Proc. 26(e)(1) requires a party to supplement  its disclosures "if the party learns that in some material respect the  information disclosed is incomplete or incorrect and if the additional  or corrective information has not otherwise been made known to the  other parties during the discovery process or in writing."  As we have  noted previously, the supplement requirement helps a party avoid the  burden of responding to unexpected and last-minute changes in its  opponent's expert testimony.  See Licciardi, 140 F.3d at 363.  This, in  turn,  promotes the broader purpose of discovery, which is "the  narrowing of issues and the elimination of surprise."  Johnson v. H.K.  Webster, Inc., 775 F.2d 1, 7 (1st Cir. 1985) (internal quotation marks  omitted).


31
Asia Badger asserts that, as an initial matter, it did not  violate Rule 26 because Dr. Kennedy was originally scheduled to testify  after the close of appellee's case.  Since by this time Dr.aHaig's  report would have been introduced into evidence by appellee, Dr.  Kennedy would be qualified to testify based on the Haig report pursuant  to Fed. R. Evid. 703, which states that "[t]he facts or data in the  particular case upon which an expert bases an opinion or inference may  be those perceived by or made known to him at or before the hearing."  Fed. R. Evid. 703.  According to Asia Badger, although Dr. Kennedy had  to testify earlier than planned due to scheduling conflicts, the same  result should ensue.


32
We are not persuaded by this evidentiary sleight of hand. It  seems clear that Rule 703, which outlines the permissible bases for  expert testimony, was not designed to thwart the goals of open and fair  discovery embraced by Rule 26.  Here, Dr. Kennedy revealed during voir  dire that Dr. Haig's report -- written in 1995 -- was provided to him  by Asia Badger at least three weeks prior to trial.  In addition, Asia  Badger itself introduced the report and questioned Dr. Kennedy on its  contents, suggesting that it was aware of his changed opinion.  Thus,  even if appellee intended to introduce Dr. Haig's report before Dr.  Kennedy testified (which is itself uncertain), Asia Badger would not be  excused from its duty to abide by the rules of discovery and inform  appellee of the change in the expert's pretrial report.  See Licciardi,  140 F.3d at 365 (defendant required to inform plaintiff of material  change in expert's opinion, even where plaintiff might have reason to  expect that it might change); see also Thibeault v. Square D Co., 960  F.2d 239, 244 (1st Cir. 1992) (emphasizing that this Court attempts "to  ensure that the spirit of open discovery embodied in Rule 26 is not  undermined either by evasion or dilatory tactics").  Furthermore,  appellant offered no explanation whatsoever for its failure to amend  Dr. Kennedy's reports to reflect his new opinion.  There is thus ample  support in the record for the district court's conclusion that Asia  Badger stood in violation of Rule 26(e)(1), and we do not believe that  Rule 703 was intended to end-run this basic requirement of fair play.


33
When faced with a discovery violation, the district court  "possesses wide latitude in formulating the appropriate sanction." Poulin v. Greer, 18 F.3d 979, 984 (1st Cir. 1994).  Under the Federal  Rules of Civil Procedure, a party that fails to disclose information  under Rule 26(e)(1) "shall not . . . be permitted to use as evidence .  . . any witness or information not so disclosed."  Fed. R. Civ. P.  37(c).   Although the court originally ruled to exclude all of Dr.  Kennedy's testimony -- a sanction well within the district court's  scope of discretion -- the court ultimately decided to strike only  those portions of Dr. Kennedy's testimony based on the passage in Dr.  Haig's report describing Sheek's activities in Saudi Arabia.  It is  true, as Asia Badger points out, that causality was an important issue  in this case.  However, Dr.aHaig's report itself remained in evidence,  and the jury was free to infer, as Asia Badger argued in its closing,  that Sheek's activities in Saudi Arabia contributed to his injury. Given its minimal impact on appellant's case, the district court's  sanction was relatively lenient and we see no reason to disturb it.

2.  Sheek and Syar's Testimony

34
Asia Badger challenges the admission of (1) Sheek's testimony  that the cooling water issue was a "design" problem rather than a  maintenance problem and that Asia Badger was responsible for the design  work; (2) Sheek's testimony regarding the purpose of the repiping work;  and (3) Sheek's rebuttal testimony that the work done in August of 1994  described by Ch Tai was not the same work done in March of that year. Appellant also challenges Syar's deposition testimony that Asia Badger  handled the repiping work in March of 1994, arguing that Syar did not  personally observe the work being done.  We review evidentiary issues  for abuse of discretion.  Kelley v. Airborne Freight Corp., 140 F.3d  335, 345 (1st Cir. 1998).


35
Fed. R. Evid. 602 requires that a witness have "personal  knowledge" about the matter to which he testifies.  Such knowledge can  include "inferences and opinions, so long as they are grounded in  personal observations and experience."  United States v. Rodrguez, 162  F.3d 135, 144 (1st Cir. 1998) (quoting United States v. Neal, 36 F.3d  1190, 1206 (1st Cir. 1994)); see also Fed. R. Evid. 701.  We believe  that the record supports the district court's conclusion that Sheek and  Syar met this threshold in each of their disputed statements.


36
First, as his testimony reveals, Sheek had been a Mobil  employee for twenty-eight years, beginning as an operator in a chemical  processing unit.  He later worked as a controlman and then as a  production supervisor during the construction of new Mobil plants in  the United States and abroad.  By the time he arrived in Singapore,  Sheek had completed two years of pre-engineering work in Cambridge,  Massachusetts, which involved reviewing drawings and providing input  into the design of the Project.  During his day duty, Sheek was  personally responsible for relaying, directly or indirectly, all punch  list items to Asia Badger.  Finally, Sheek also observed a memorandum  from Asia Badger outlining the modifications of the piping.2  Combined,  these factors provided a sufficient foundation for Sheek to identify  the cooling water issue as a design defect and to infer that Asia  Badger had performed the design work.  Given his experience and  observations, moreover, Sheek was qualified to testify that the purpose  of the repiping was to increase the flow of the cooling water -- a fact  that appears uncontroverted by both parties.


37
Sheek's rebuttal testimony did not even require inference or  opinion, but was grounded in his personal observations alone. According to the deposition testimony of Ch Tai, Mobil performed  modifications on the cooling water pipes that led to the xylene  splitter pumps in August 1994.  This work allegedly took place in the  aromatics unit, an area that Sheek supervised for a period of three  months.  Sheek countered that during one of his shifts in March 1994,  he observed that the piping in the D pump had been changed to a larger  diameter size. Sheek therefore had the personal knowledge to not only  distinguish the work described by Tai (on the pipes leading to the  pumps) from that which he observed (within the pump itself), but also  to testify that they involved different locations within the aromatics  unit.


38
Finally, the court properly admitted James Syar's testimony  that Asia Badger performed the repiping work.  Syar's deposition  testimony included the following colloquy:


39
Q:      Okay.  When you say December and April are you talking about  December '93 and April '94?


40
A:      Yes.


41
Q:      All right.  You were on the night shift that whole time  period?


42
A:      Yes.


43
Q:      Okay.  Now, the work being done on these cooling water  pipes, that was done during the daytime?


44
A:      Most of them were done -- yeah, because we were limited to  what we could have done at night.


45
Q:      Okay.  So it's yes that they -- that they were?


46
A:      Yes.


47
Q:      Okay.  So you couldn't have actually seen the work being  done, is that right?


48
A:      On that particular pipe, no.  I-piping, only if they were  there, worked over at night.


49
Q:      And did they?


50
A:      I was there for some of it.  Now, for the main header, that  was done during the day.  Most of the time what we dealt  with was just what connected to our pumps so....


51
Q:      All right.  Tell me -- tell me the dates when you actually  saw the work being done at night.


52
A:      I can't.  I can't do that.


53
Although appellant makes much of the court's initial impression that  the testimony was "unclear," the court subsequently concluded that  Syar's testimony indicated that some of the repiping work took place at  night, while he was working.  In fact, Syar affirmatively responded  that some of the work took place in his presence.  The fact that Syar  was unable to specify the dates on which he saw the work being done may  affect the weight, but not the admissibility, of his testimony.  SeeNeal, 36 F.3d at 1206.  Viewing his statements as a whole, Syar  demonstrated sufficient personal knowledge to testify to the party  responsible for the repiping work on the xylene pumps.


54
In sum, we hold that the district court did not abuse its  discretion in admitting any of the testimony claimed as error by  appellant.

B.  Jury Instructions

55
Asia Badger next contends that the district court provided  misleading and confusing instructions on the issue of vicarious  liability and then exacerbated that error through a poorly-worded  special verdict form.  Once again, we cannot agree.

1.  The Jury Charge

56
According to Asia Badger, the district court erred when it  refused its request to "enumerate and clarify the standard" for  vicarious liability.3  Because Asia Badger objected to the court's  instructions before the jury retired, it met the requirements of Fed.  R. Civ. P. 51 and must be reviewed to see whether there was error and,  if so, whether it was harmless.  Beatty v. Michael Bus. Mach. Corp.,  172 F.3d 117, 121 (1st Cir. 1999).  To this end,


57
[t]he rules of decision are uncontroversial. "The  trial court's refusal to give a particular  instruction constitutes reversible error only if  the requested instruction was (1) correct as a  matter of substantive law, (2) not substantially  incorporated into the charge as rendered, and (3)  integral to an important point in the case." Elliott v. S.D. Warren Co., 134 F.3d 1, 6 (1st  Cir. 1998) (quoting United States v. DeStefano,  59 F.3d 1, 2 (1st Cir. 1995)). Similarly, the  giving of an instruction is reversible error only  if it (1) was misleading, unduly complicating, or  incorrect as a matter of law, and (2) adversely  affected the objecting party's substantial  rights.  Levinsky's Inc. v. Wal-Mart Stores,  Inc., 127 F.3d 122, 135 (1st Cir. 1997).


58
Faigin v. Kelly, 184 F.3d 67, 86-87 (1st Cir. 1999).  Using these  guidelines, we discern no error in the district court's instruction.


59
Asia Badger meets the first and third prongs of the test for  the court's refusal to accept its proffered instruction.  Both parties  agree that Singapore law governs the issue of vicarious liability.  For  this issue, both Sheek and Asia Badger cite as authority Mohd bin Sapri v. Soil-Build Private Ltd., 1996 SLR Lexis 324 (Sing. Ct. App. 1996),  which held that a party was not liable for the negligent act of its  subcontractor because the party did not control the work of the  subcontractors and was not involved in any substantial supervisory or  coordinating capacity.  Id. at *29 ("[The party] had left the matter  entirely to is sub-contractors.").  Distinguishing the facts in Soil-Build from an English case where such liability was found to exist, McArdle v. Andmac Roofing Co., 1 Eng. Rep. 583 (Eng. C.A. 1967), the  Singapore court highlighted two scenarios where a contractor may be  liable for the negligence of its subcontractors.4  Soil-Build, 1996 SLR  Lexis 61 at *28.  First, the party may be liable where the working  conditions are inherently dangerous, thereby "requiring the exercise of  a significant degree of supervision and control over persons with whom  he has no contractual relationship."  Id.  Alternatively, the party may  owe a duty of care if "he [has] taken it upon himself to exercise a  degree of control and actively coordinate the [sub]contractors'  activities, given that the work environment itself involved inherent  risks or danger."  Id.


60
The record suggests that the parties and the court took the  second route for determining liability.  To be sure, Sheek did not  argue that Asia Badger was required to exercise control over its  subcontractors or third parties due to the "inherent danger" of the  work and facilities, nor did Asia Badger defend on this theory. Rather, the issue presented to the jury was whether Asia Badger did, in  practice, exercise control over the claimed repiping work, which would  lead to a duty of care to Sheek.  On this point, Asia Badger's proposed  instruction was correct as a matter of substantive law: it required the  jury to find that an Asia Badger employee "personally supervised and  directed the manner and details of the doing of the work of that  subcontractor" in order to be liable for the negligence of its  subcontractor.5  It is unquestionable, moreover, that the issue of  vicarious liability was integral to an important point -- perhaps the  most important point -- of the case.


61
Nevertheless, the refusal to incorporate the exact wording  offered by the appellant will not constitute error unless the court  failed to substantially incorporate the offered theory in its  instruction.  Elliott, 134 F.3d at 6.  According to Asia Badger, the  court did not properly instruct the jury on the elements of vicarious  liability, namely, that a party must have control over "the details and  the manner of the work to be done" by the subcontractor.  However, we  can find no disparity between this concept and the court's charge to  the jury.  The court explicitly noted that the jury was required to  find that Asia Badger exercised "direct control, not only over what  work was to be done, but the actual performance of work of the  subcontractor as well."  This indicated to the jury that it was to  consider both the "details and the manner" of the work performed.  When  the court has sufficiently conveyed a litigant's theory, that litigant  is not "entitled to dictate the turn of phrase the judge should use to  acquaint lay jurors with the applicable law."  Id.  We therefore uphold  the district court's refusal to give the instructions offered by Asia  Badger.


62
However, Asia Badger also claims that the given instruction,  though incorporating its theory of applicable law, nonetheless confused  and misled the jury.  We find this contention without merit.  If  anything, the court condensed the lengthy and somewhat repetitive  instruction offered by Asia Badger into concise and straightforward  language that would be more easily comprehended by the jury.  See id. at 7 (decision to give a general statement of law in order to avoid  potential confusion from proffered instruction by counsel lies  "uniquely within the trial judge's discretion").  As we noted above,  the court offered a correct statement of the law, and appellant has  failed to identify any misleading or unduly complicating aspect of the  given instruction.  Since we find none, we hold that there was no error  in the jury charge rendered by the district court.


63
We also reject appellant's challenge to the adequacy of the  court's response to the jury's query.  We acknowledge that jury  instructions given during the course of deliberations come "at a  particularly delicate juncture" and require the court to construct its  wording carefully.  Testa v. Wal-Mart Stores, Inc., 144 F.3d 173, 175  (1st Cir. 1998) (warning that "the court can err as easily by  overinclusiveness as by underinclusiveness").  However, we have also  noted that as long as the court correctly addresses the issue submitted  by the jury, it may amplify the instruction at its discretion.   Seeid. at 176.  The court here, after reminding the jury that it first  needed to resolve the issue of negligence, proceeded to explain that  Mr. Sheek's negligence could include either the time of the accident or  "some later period," depending on the nature of the injury.  While it  may be true that the court could have phrased its answer more simply,  we find no basis to conclude that the instruction was confusing,  misdirecting, or misleading. See Steckstor v. Hancock, 984 F.2d 274,  278 (8th Cir. 1993) (concluding that district court's reference to  insurance in answering jury's question concerning liability, though  "unfortunate," was not error). We presume that the jury followed the  court's instruction,  United States v. Gonzalez-Vazquez, 219 F.3d 37,  48 (1st Cir. 2000), and Asia Badger's disappointment that the award was  reduced by "only" ten percent for comparative negligence does little to  rebut this presumption.

2.  Verdict Form

64
Asia Badger also objects to the wording of the verdict form,  which it argues conflated the issues of direct and vicarious liability. A verdict form must be "reasonably capable of an interpretation that  would allow the jury to address all factual issues essential to  judgment." Johnson v. Teamsters Local 559, 102 F.3d 21, 28 (1st Cir.  1996) (quoting United States v. Real Property Located at 20832 Big Rock  Dr., 51 F.3d 1402, 1408 (9th Cir. 1995)). We examine the court's  instructions to the jury and the wording on the verdict form as a whole  to determine whether the issues were fairly presented to the jury.  Id. at 28.


65
As we have already discussed, the court clearly instructed  the jury on the requirements for vicarious liability.  The court also  separately addressed Asia Badger's direct liability for its own  employees.  Given this distinction, the jury could reasonably interpret  the phrase "employees or agents" included in Question 1 of the verdict  form to refer to employees or subcontractors and hence, the respective  theories of direct and vicarious liability.  If "the general charge  adequately directs the jury to its duties in answering the questions  submitted to it there is no need to accompany the submission with  repetitive instruction."  Id. (quoting Lawrence v. Gulf Oil Corp., 375  F.2d 427, 429 (3d Cir. 1967)).  Since the jury was so directed, we hold  that the court was not required to ask separate questions concerning  direct and vicarious liability in the verdict form.

C.  Sufficiency of the Evidence

66
Finally, Asia Badger maintains that the district court erred  in refusing its motions for judgment notwithstanding the verdict and  new trial, because the evidence was insufficient as a matter of law to  sustain the jury's verdict.  Specifically, Asia Badger contends that  Sheek failed to establish two crucial elements of his claim: that Asia  Badger or its subcontractors actually performed the repiping work in  March 1994 and that Asia Badger exercised control over any work so  performed.  Our standard of review is de novo, viewing all facts and  inferences in the light most favorable to the verdict.  Sinai v. New  England Tel. & Tel. Co., 3 F.3d 471, 472 (1st Cir. 1993).


67
First, Asia Badger contends that the evidence establishes,  "unequivocally," that Mobil did the repiping work.  The facts and  inferences most favorable to Sheek, however, suggest otherwise.  Sheek  testified that on March 8, 1994, he took the D pump out of service. The next evening, he observed that some of the piping within the pump  had been changed to a larger diameter.  A jury could reasonably infer,  despite Tai's testimony to the contrary, that some repiping work was  indeed performed on the pumps in March of 1994.6  With respect to the  March 1994 work, moreover, Sheek conceded that Mobil performed  maintenance work -- such as replacing the seals -- on the xylene pumps. He noted, however, that in the course of this work, any piping that was  removed would necessarily have to be reconnected.  Based on this  testimony, a jury could reasonably believe that the pipe on which Sheek  slipped could not be related to the work done by Mobil.  Finally, Asia  Badger's performance of some punch list work,7 Sheek's observation of  a memorandum from Asia Badger outlining repiping work to be done in the  field, and the fact that some work on the pumps was performed at night  by Asia Badger in Syar's presence all provide a sufficient foundation  for the conclusion that work done on the pumps in March 1994 was done  by Asia Badger or one of its subcontractors.


68
We also believe that there was sufficient evidence for the  jury to find that any work performed was done under the supervision of  Asia Badger.  Asia Badger emphasizes that no one witnessed Asia Badger  exercise control over a subcontractor after January 1994.  However,  Sheek testified that during his day duties in late 1993, he saw Asia  Badger employees actually directing work done by its subcontractors. Steinmetz further testified that Asia Badger's work continued in the  same manner before and after January 1994.  Taken together, these two  pieces of evidence could, as the district court noted, support the  inference that Asia Badger controlled the work done by its  subcontractors in the period from January to March of 1994 in the same  way that Sheek described this control before January 1994.


69
Although Asia Badger presents numerous inconsistencies and  alternative theories based on the facts, we do "not consider the  credibility of witnesses, resolve conflicts in testimony, or evaluate  the weight of the evidence."  Hendricks & Assoc., Inc. v. Daewoo Corp.,  923 F.2d 209, 214 (1st Cir. 1991) (quoting Wagenmann v. Adams, 829 F.2d  196, 200 (1st Cir. 1987)).  Rather, we will uphold the jury's verdict  unless the evidence points "to one conclusion and one conclusion only:  that the losing party was entitled to win."  Sinai, 3 F.3d at 473.  Without a doubt, the facts here are myriad and conflicting.  Wading  through this morass, however, we believe there is enough evidence to  support the jury's verdict in favor of Sheek.

III.  CONCLUSION

70
The judgment of the district court is affirmed in all  respects.



Notes:


1
   Question Number 3 asked, "Was Jack Sheek negligent?"


2
   The district court properly admitted this testimony as an admission  by a party opponent.  Fed. R. Evid. 801(d)(2).


3
   Asia Badger's request included the following instruction:
1. The burden is on Mr. Sheek to prove by a preponderance of the  evidence that it was an Asia Badger employee, and not any other  person or entity, who failed to use reasonable care with regard  to the pipe which is alleged to have caused the plaintiff's  injury.
2. If you believe that another person or entity failed to use  reasonable care with regard to the pipe, including an Asia Badger  subcontractor, then Asia Badger is not liable unless Asia Badger  actually exercised direct detailed control over [the] manner of  the doing of the work of the person or entity or subcontractor who  failed to use reasonable care with regard to the pipe.
3. In this case, Asia Badger is only liable for the actions of one  of its subcontractors if an Asia Badger employee personally  supervised and directed the manner and details of the doing of the  work of that subcontractor.
4. Direct supervision and control is more than retention of the general rights of watching over the progress of the work which the  subcontractor agreed to do.  You must find that Mr. Sheek has  proved by a preponderance of the evidence that Asia Badger not  only determined the work to be done but that an Asia Badger  employee exercised direct control over the actual performance of  the work which caused the injury.  This means  that there must be  actual control and direction of the details of the manner in which  the subcontractor performed the allegedly negligent work.
5. For example, if an Asia Badger employee was at the location of the  subcontractor's work and personally directed the work of the  subcontractor's workers, including the details and manner in which  the work to be done, and the subcontractor's workers took  instructions from him, then Asia Badger would be liable for the  work.  On the other hand, if no Asia Badger employee personally  directed the work of the subcontractor's workers, then Asia Badger  is not liable.  In addition, if Asia Badger directed the  subcontractor what work was to be done, but did not provide  detailed control over the manner of the doing of the work, then  Asia Badger is not liable.
6. Thus, if you find that Mr. Sheek has not shown by a preponderance  of the evidence that Asia Badger exercised direct control over the  manner in which the persons or entities performed the work that  caused Mr. Sheek's injury, then you must find in favor of Asia  Badger.


4
   It should be noted that the court was concerned with a party's  liability towards the employees of its subcontractor, rather than  towards third parties in general.  See Soil-Build, 1996 SLR Lexis  61  at *28.


5
   Asia Badger appears to have taken this statement of law from McArdle,  as articulated by the Singapore court.  Soil-Build, 1996 SLR Lexis 61  at *17 ("[In McArdle, the party] personally directed the work of the  sub-contractors, including the details and manner in which the work was  to be done.")


6
   In fact, a jury need not even disbelieve Tai to arrive at this  conclusion: since Sheek identified the August 1994 work described by  Tai as "further downstream" from the work he himself observed, the  conclusion that someone changed the piping within the pumps in March  1994 is not inconsistent with Mobil's replacement of the piping leading  from the pumps to the main headers in August 1994.  Similarly, refuting  appellant's claim that Asia Badger did not "use" schedule 40 pipe is  not a sine qua non of Sheek's case, as appellant would have us believe. On the contrary, Sheek identified schedule 40 pipe as the type being  removed from within the pumps.  It is entirely possible, then, that  Asia Badger, while not utilizing this type of pipe in its own work,  nevertheless removed this type of piping from a pump manufactured by  someone else.


7
   Steinmetz testified that both Mobil and Asia Badger took  responsibility for punch list work after January 1994.  Although Asia  Badger claims that there is no evidence that the repiping formed part  of the punch list work, Sheek's definition of a "punch list" as an  "operational problem" supports the inference that the pumps' piping  problem would be included on this list.


