It was ten o’clock he returned home.A. \ …whenB. at …whenC. at …thatD. \...that

问题补充：

It was ten o’clock he returned home.

A. \ …when

B. at …when

C. at …that

D. \...that

答案：

(答案→)A. \ …when

B. at …when

C. at …that

D. \...that

解析：第一空考查介词，在时间点前用at；第二空考查时间状语从句。 句意：当他回家时已是十点了。