Question

Robert saw two boys making fun ________ an old man, and then he stopped them.

A．in	B．on
C．at	D．of

Answer 1

D

試題分析：句意：羅伯特看到兩個男孩在開一個老人的玩笑，然后他阻止了他們。make fun of sb開……的玩笑。根據句意，故選D。