问题

The students _ busily when Miss Brown went to get a book she _in the office

A:might have saved
B:must have saved
C:should have saved
D:could have saved

正确答案是：

同类题型

It is only in the last sixty years that________any evidence that Loch Ness Monster might exist

The person sitting opposite _____ Mr．Smith is our new manager．

Has John ____ Beijing _____ Shanghai

My grandparents _________for fifty years and they areboth quite healthy now.

It’s dangerous to swim in this lake.— Yes， you are right. The government has people not to swim in it.