After______ seemed like hours he came out with a bitter smile.

A. which　　 B. it　　　　 C. what　       D. that

选C

句意：过了似乎有几个小时的时间，他苦笑着出来了。

分析：after 在此处是介词，what (= the time that) 引导宾语从句。

本题易误选B，认为after作连词，it作主语，指代时间，这种理解错误在于after后接一段时间名词时，after是做介词还是连词？

试看《新牛津英汉双解大词典》的解释：

after作介词时，意为：with a period of time rather than an event 在（一段时间）之后

例如：After a while he returned. 过了一会儿他回来了。

after作连词时，意为：during the period of time following (an event) 在…之后；后来

Bath time ended in a flood after the taps were left running. 水龙头没关，人走后浴室里一片汪洋。

所以上题中after只能作介词，而不是连词，答案为C。类似的句子：

After what seemed ages, the newsman disclosed the fact.

After what seemed ages of waiting, the applicants were finally informed of the result of the job interview.

After what seemed ages, he promised that he would wreak away from that party.