He forgot to lock the door of course made things even worse.A. whoB. whomC. whichD. wha

问题补充：

He forgot to lock the door, of course, made things even worse.

A. who

B. whom

C. which

D. what

答案：

A. who

B. whom

(答案→)C. which

D. what

解析：句意：他忘记了锁门，当然这使得事情更糟。这里是非限制性定语从句，which引导非限制性定语从句，指代前面的句子，而且在从句中做主语，选C。