It is not until we know more about the situation we are able to improve it.A. thatB. what

问题补充：

It is not until we know more about the situation we are able to improve it.

A. that

B. what

C. when

D. which

答案：

(答案→)A. that

B. what

C. when

D. which

解析：考查强调句。本句是对not until引导的时间状语从句进行强调。It is not until…that…。