问题

Our monitor always comes to our help when we get into trouble _______ she is very busy.

A:since
B:once
C:even if
D:if;

正确答案是：

同类题型

22．If we know more about _______causes the problem, we may take measures before it is _______late

She_______ at home last night.

There are ________of animals in the zoo.

_____________ the doctor , the old man is out of danger.

e been looking at houses, but haven’t found_____ we like yet