The library needs ________, but I won't have it done until tomorrow morning.

[　　]

The light in the classroom is still on. Oh, I forgot ________.

[　　]

To make up an objective test, the teacher writes a series of questions, ________ has only one correct answer.

[　　]

I will move to a new department ________ more knowledge is required.

[　　]

They came back ________ way they went.

[　　]

　　Who left the door open that day?

　　 ________.

[　　]

We ought to help each other, ______?

[　　]

A．oughtn't we　　　B．don't we

C．should we　　　　D．wouldn't we

I always consider this ______ of the two books.

[　　]

A．the best　　　B．best　　　C．the better　　　D．better

Though he ______ for many years, we still think that his death is ______ than Mount Tai. 

[　　]

A．has died...weightier

B．has been dead...weightier

C．has died...heavier

D．has been dead...heavier

Mr Hopkins told Jenny that she would never pass the exam ______ she worked harder.

[　　]

A．if　　　B．when　　　C．unless　　　D．while