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：本题考查not until的强调句型。It is /was not until …… that ……