It was not until midnight they reached the camp site. A. thatB. whenC. whileD. as

问题补充：

It was not until midnight they reached the camp site.

A. that

B. when

C. while

D. as

答案：

(答案→)A. that

B. when

C. while

D. as

解析：句意：他们直到半夜才到达宿营地。本句考查强调结构，可以还原为：They didn’t reach the camp site until midnight. 这是含有until引导状语从句的强调句型。当强调 until从句部分时，应注意把not一起提前。即：It is/ was not until + 被强调部分 + that + 其它部分。