Even after many years, he still recognizes his old classmate at first glance.

recognizes 是动词 recognize 的第三人称单数现在时形式。recognize 由前缀 re-（表示"再次"）和词根 cognize（认知）组成，意思是"认出、识别、承认"。在这里指"认出某人"的动作。