He was shocked at the junk food that he saw____when he was in the restaurant

问题描述:

He was shocked at the junk food that he saw____when he was in the restaurant
A.was served B.tobe served C.being served D.having served

答案是 C.being served语境需要进行时态和被动语态sth being servedHe saw food being served by the waiterHe saw a man being run over by a carHe saw a bird being eaten by a cat