It was not until Tom took off his dark glasses that I him.A. recognizedB. knewC. discover

问题补充：

It was not until Tom took off his dark glasses that I him.

A. recognized

B. knew

C. discovered

D. realized

答案：

(答案→)A. recognized

B. knew

C. discovered

D. realized

解析：考查动词。A recognized辨认；B knew知道；C discovered发现；D realized意识到。句意：直到汤姆摘掉墨镜，我才认出他来。故A正确。