Not until the meeting was over ____ that he had made a mistake in his speechA he realized B did he realize C he has realized D has he realized为什么选b?
问题描述：
Not until the meeting was over ____ that he had made a mistake in his speech
A he realized B did he realize C he has realized D has he realized
为什么选b?
答
not until 放在句首，主谓要部分倒装。
类似情况是，否定词像 no,never,hardly ,scarcely ,seldom 等放在句首时，主谓用部分倒装。
如：Hardly had he put down the receiver when the phone rang again .
答
首先not until 在句首，句子要半倒装，其次，整个句子是过去时，所以用一般过去时表示过去发生的事情。
答
因为not until开头
句子要用倒装
排除A C
D的话因为后面用had made
所以整个句子要用过去式
所以选B
答
not until 引导的从句主句要用倒装，所以排除A.C而错误已经犯了，是在意识到之前就犯的，所以意识是用过去时，而犯错是用过去的过去，懂了吗