Question

Not until he left his home ______ to know how important the family was for him.

A．did he begin	B．had he began
C．he began	D．he had begun

Answer 1

A

考查倒装句。Not until…位于句首，主谓应部分倒装。又因为begin不是发生于left之前，故不需用过去完成时。