It was at 12 o’clock they came home from school.A. whatB. whenC. thatD. Which

问题补充：

It was at 12 o’clock they came home from school.

A. what

B. when

C. that

D. Which

答案：

A. what

B. when

C. that

D. Which

解析：句意：他们从学校到家的时间正是在十二点钟。根据句意强调他们回到家是在十二点，英语中强调句型结构为：It is/was +被强调部分+that ...。在这里that不可变成其他词。虽然强调时间依然不能用when。

考点:考查强调句式的用法。