问题
选择题
Not until he left his home ______ to know how important the family was for him.
A．had he begun
B．did he begin
C．he began
D．he had begun
答案
答案：B
考察倒装句。Not until放在句首的时候，后面的句子使有部分倒装的形式，故排除CD。再看时态，本句不需要使用过去完成时。句意：直到他离开家，他才知道家对他来说是多么重要。