In fact there are so many deer that some _____ to places which would like to return this kind of deer to the wild．

[　　]

Food shortage will long be a problem _____ much has been done to support enough for everyone.

[　　]

It's very dangerous to use those machines that _______.

[　　]

The pupils _______ doing their exercises in the classroom now by their teacher.

[　　]

A．have kept busy

B．are busy

C．are keeping busy

D．are being kept busy

--Have you moved into the new house?

--Not yet. The rooms _______.

[　　]

In order ________,one should do one's best．

[　　]

A．to be defeated

B，to not be defeated

C．not to defeat

D．not to be defeated

In some western countries, tea __________ with sugar and milk.

[　　]

Air is to us ___________ water is to fish.

[　　]

He _________ know it. I didn't tell a word of it.

[　　]

After a long discussion, they __________ up with a new solution to the problem.

[　　]