—Appeal by the defendant from a judgment of the County Court, Nassau County (Mogil, J.), rendered July 10, 1992, convicting him of criminal sale of a controlled substance in the third degree and criminal possession of a controlled substance in the third degree, upon a jury verdict, and imposing sentence.
Ordered that the judgment is affirmed.
Contrary to the defendant’s contention, the trial court’s rulings during the cross-examination of the People’s police witnesses did not deprive him of a fair trial (see, People v De Jesus, 42 NY2d 519).
*695The trial court did not improvidently exercise its discretion in sustaining certain objections which were made by the prosecutor during defense counsel’s summation (see, People v Barreau, 183 AD2d 904).
The expert testimony of a qualified expert with regard to street-level drug transactions involving several participants neither invaded the jury’s province nor bolstered the testimony of the People’s eyewitnesses (see, People v Cronin, 60 NY2d 430; People v White, 184 AD2d 798; People v Right, 180 AD2d 430).
We have considered the defendant’s remaining contentions and find them to be without merit. Rosenblatt, J. P., Lawrence, Altman and Goldstein, JJ., concur.