In Bonds v. Roy (1999) 20 Cal.4th 140, a medical malpractice case, the defendant stated in his expert witness declaration that his expert would testify only on the issue of damages. At the expert's deposition, the expert "specifically confirmed he did not expect 'to be giving any testimony or any opinion concerning the standard of care issues that might be involved in this case.'" (Id. at p. 143.) At trial, during the afternoon recess of the last day of testimony, defense counsel sought to expand the scope of the expert's testimony to include the applicable standard of care. The trial court denied the request on two grounds: first, the plaintiff had expected the expert to testify only as to damages and "because the expert was the last defense witness, there was not enough time to adjourn and take his deposition;" second, expanding the "scope of the expert's testimony at that point would be unfair, prejudicial, and a surprise to the plaintiff." (Ibid.) The Supreme Court affirmed, explaining: "the very purpose of the expert witness discovery statute is to give fair notice of what an expert will say at trial. This allows the parties to assess whether to take the expert's deposition, to fully explore the relevant subject area at any such deposition, and to select an expert who can respond with a competing opinion on that subject area." (Id. at pp. 146-147.) The Court continued, "when an expert is permitted to testify at trial on a wholly undisclosed subject area, opposing parties similarly lack a fair opportunity to prepare for cross-examination or rebuttal." (Id. at p. 147.) In sum, the defendant sought to expand the scope of his expert witness on the last day of defense testimony. ( Id. at p. 143.) The trial court denied the request, noting that changing the scope of the witness's testimony at that point in the trial was prejudicial and a surprise and that there was not enough time to adjourn and take the witness's deposition. (Ibid.) The Supreme Court upheld the trial court's ruling, reasoning that the court acted within its discretion to limit the witness's testimony to that which was previously disclosed in the expert witness declaration. ( Id. at p. 149.) The court further noted that the defendant's late request to expand the scope of the witness testimony did not allow a practical opportunity to depose the expert. (Ibid.) The Supreme Court held that under Code of Civil Procedure former section 2034, "which provide[d] for discovery of expert witness information, a trial court may preclude an expert witness from testifying at trial on a subject whose general substance was not previously described in an expert witness declaration." (Bonds, supra, at p. 142.) In that case, an expert witness was deemed precluded from testifying regarding the standard of care because the plaintiff's expert declaration had stated he would address the issue of damages only. The Supreme Court found that, under the relevant discovery statutes, the expert's testimony was properly limited to that which had been disclosed in his expert declaration. (Id. at p. 149.)