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 _______.

[　　]

Hundreds of jobs ________ if the factory closes.

[　　]

After the war a new school building was put up ________ there had once been a theatre.

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The famous scientist grew up _________ he was born and in 1930 he came to Shanghai.

[　　]

Beyond ________ stars,the astronaut saw nothing but ________ space.

[　　]

John shut everybody out of the kitchen _________ he could prepare his

grand surprise for the party.

[　　]

--What happened to the postman?

--I don't know. He_________around here for a long time.

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