Question

Not until they left school ____how much their teachers loved them and helped them.

A．that they realized	B．had they realized
C．when they would realize	D．did they realize

Answer 1

D

解析试题分析：考查倒装句，not until+从句置于句首，主句用部分倒装，助动词/be动词/情态动词放在主语前面，BD都是倒装，因为他们先离开学校才意识到老师多么爱他们，所以是过去时。选D。
考点：考查倒装句
点评：否定词放在句首要用部分倒装句，包括not until，要注意的是not until后面的从句不倒装，主句倒装。