问题

When did your father come back last night— He didn’t come back _______ he finished all thework.

A:until
B:while
C:if
D:unless

正确答案是：

同类题型

derson is popular with his students, for heis kind, strict and knowledgeable— No wonder he has such a good_________

We are supposed to recycle paper and bottles. It can help the environment.—_________. It can save money, too.

Mother was busy washing dishes ________________ Father was watching TV．

If only I＿＿＿＿＿how to operate a computer as you do!

I didn’t know .