JOHNSON, Judge.

James Stewart Smith sued William Curtis for injuries he sustained in an automobile accident. Smith's wife, Catherine Smith, sued for loss of consortium. The jury returned a verdict awarding $3,500 in damages to Mr. Smith and no damages to Mrs. Smith. The Smiths appeal from the judgment entered on the verdict and the denial of their motion for new trial, arguing that the trial court erred in refusing to give one of their requested charges. For the reasons set out below, we affirm the judgment of the trial court.

1. The requested charge provided that if the jury finds Mr. Smith's back injury resulted from the combined negligence of Curtis and the negligence of another motorist in a previous accident, Curtis bears the burden of showing how liability should be apportioned between the two tortfeasors. In a charge conference held prior to the court instructing the jury, the trial judge informed counsel that he would not give the requested charge because another charge covered the same principle. Counsel for the Smiths objected to the court's refusal to give the charge, arguing that the charge reflects the present state of the law in Georgia. The trial court did not give the requested charge to the jury and, at the conclusion of the jury charge, the trial judge asked counsel for the Smiths if he had anything to say about the court's charge. Smiths' counsel replied that he did not. Under these circumstances, the Smiths have waived their objection to the jury charge.

First, by responding to the court's inquiry at the end of the jury charge that he had nothing to say about the charge, counsel expressly acquiesced in the jury charge as given. As a result, any objection to the omission of the requested charge was waived. See Bell v. Samaritano, 196 Ga. App. 612, 613 (2) ( 396 S.E.2d 520) (1990); Phillips v. State, 176 Ga. App. 834, 835 (1) ( 338 S.E.2d 57) (1985); Salmon v. State, 249 Ga. 785, 786-787 (3) ( 294 S.E.2d 500) (1982); see also Roura v. State, 214 Ga. App. 43, 45 (2) (a) ( 447 S.E.2d 52) (1994).

Second, an objection to an instruction made only at a charge conference is insufficient to preserve the matter for appellate review. Brown v. Sims, 174 Ga. App. 243, 244 (2) ( 329 S.E.2d 523) (1985); Mack v. Barnes, 128 Ga. App. 328, 329-330 (2) ( 196 S.E.2d 684) (1973); see Rice v. Rumph, 171 Ga. App. 301 ( 319 S.E.2d 125) (1984). In order to preserve the issue, the Smiths were required to renew their objection to the court's refusal to give the requested charge after the court instructed the jury, but they did not. See Wilson v. State, 259 Ga. 55, 58 (6) ( 376 S.E.2d 676) (1989); Whelchel v. Thomas Ford Tractor, 190 Ga. App. 156 ( 378 S.E.2d 510) (1989). Accordingly, the objection was not preserved for our review.

2. Even if the objection to the court's failure to charge had been properly preserved, no error has been shown. For a refusal to give a requested charge to be error, the request must be entirely correct, accurate, adjusted to the pleadings, law and evidence, and not otherwise covered in the general charge. Salvador v. Coppinger, 198 Ga. App. 386, 388 (1) (b) ( 401 S.E.2d 590) (1991). In order to show the requested charge was adjusted to the evidence and otherwise appropriate, the Smiths are required by the rules of this court to specifically refer to evidence in the record or the transcript which supports their claim that their injuries resulted from the combined negligence of Curtis and another tortfeasor. See Court of Appeals Rule 27 (c) (3) (i). The Smiths have made no such citations to the record or transcript. They have therefore failed to meet their burden of showing error by the record. See Studard v. Dept. of Transp., 219 Ga. App. 643, 646 (3) ( 466 S.E.2d 236) (1995); Strickland v. English, 115 Ga. App. 384 (2) ( 154 S.E.2d 710) (1967).

Furthermore, we note that the case which the Smiths cited to the trial court in support of their request to give the charge is inapposite. That case, Polston v. Boomershine Pontiac c., 262 Ga. 616 ( 423 S.E.2d 659) (1992), involves crashworthiness and enhancement of injury where the tortious conduct of another driver, the car's manufacturer and the car dealer combines to harm the plaintiff in a single accident. The instant case, on the other hand, involves two separate collisions occurring a year apart. The two accidents are not sufficiently connected to constitute the "same transaction, occurrence, or series of transactions or occurrences." Accordingly, the actors are not treated as joint tortfeasors and do not bear the burden of proving apportionment as contemplated by Polston. See Brinks Inc., v. Robinson, 215 Ga. App. 865, 866-867 (1) ( 452 S.E.2d 788) (1994). We point out that the trial court instructed the jury that if they found Curtis' negligence resulted in any aggravation of a pre-existing condition, the Smiths could recover for that aggravation.

Judgment affirmed. Pope, P.J., and Blackburn, J., concur.

JOHNSON, Judge.

DECIDED MAY 15, 1997.