I don't think ________ difficult for a Chinese student to master a foreign language within five years.

[　　]

Tom's mother kept telling him that he should work hard, but ________ didn't help.

[　　]

I don't know ________ makes her afraid of having her business discussed.

[　　]

A．what it is about Mary that

B．that is it about Mary what

C．what is it about Mary that

D．that is about Mary what

The manager didn't feel like ________ whether he would attend the meeting the next morning.

[　　]

It was those native people ________ helped the whites catch the slaves.

[    ] 　　

A. that   B. whom   C. which   D. what

－Did Li Lei call me while I was out?

－Yes, it was ________ that called you.

[　　]

Has ________ been decided when we are to hold the sports-meeting?

[　　]

　　I was disappointed with the film. 　　I had expected ________ to be much better.

　　A. that   B. this   C. one   D. it

It is important ________ their offer.

[　　]

It was ________ he said ________ disappointed me.

[　　]