求几个问题解答! 谢谢！

1． They discussed _______ they could settle the problem without others' help.

A、if

B、that

C、what

D、whether

2．A college-level course of study intended to provide students with general academic knowledge ___________ occupational training.

A、other than

B、rather than

C、more than

D、less than

3．Some facts and skills are learned by _________ activities.

A. taking

B. taking advantage of

C. keeping up with

D .giving rise to

4、The area of that city is about ________ than of this one.

A. charged

B. to be charged

C. being charged

D.to have charged

5. Do you know ________ he expects will give us a talk

A、who

B、whom

C、that

D、whose