问题
选择题
Not until they left school how much their teachers loved them and helped them.
A．they realized
B．did they realize
C．had they realized
D．they would realize
答案
答案：B
题目分析：考查倒装句和时态：句意：直到我们离开学校我们才意识到老师是多么爱我们并且帮助我们。Not until引导的时间状语从句放在句首，主句用部分倒装，因为hi在离开学校后才意识到，所以用一般过去时，选B。