We have a big library in our school. There are more than twice ________ five years ago.

[　　]

A．books than

B．as many books as

C．many books as

D．many more books than

Sometimes he ________ the teacher's question.

[　　]

A．is hesitated to answer

B．hesitate to answer

C．hesitates about answering

D．is hesitate to answer

As we stood on the top of the hill, we could see the beautiful scenes that ________ before us.

[　　]

-- What else did you do this morning besides doing the shopping?

-- Two hours ________ washing the windows and floor.

[　　]

________ difficult the task may be, we'll try our best to complete it in time.

[　　]

________ it is to travel by boat on a hot summer night!

[　　]

In a department store ________ customers.

[　　]

Nurses should be good ________ their patients.

[　　]

Mary is good ________ singing and dancing.

[　　]

Enough ________ about this subject.

[　　]