20、He made another wonderful discovery, ____ of great importance to science.

A. which I think is   B. which I think it is  C. which I think it  D. I think is 

19、She uses a wheelchair to ____ and it often takes her a little longer to do everyday things.

A. pick up        B. take off      C. get around       D. turn away

18、 ____ we are developing new technology at such a high pace ,the true challenge is to find new ways of using it.

A. Although      B. After        C. As soon as       D. Now that

17、 I hate ___ when people talk with their mouth full.

A. it            B. that         C. those           D. them

16、____ full preparations, we decided to put off the meeting till next week.

A. We didn’t make  B. Having not made  C. Not having made   D. We hadn’t made 

15、Not only the students but also the teacher ____ the result of the test.

A. is looking forward to know          B. are looking forward to knowing

C. is looking forward to knowing      D. are looking forward to know

14、Unless ____ to speak, you should remain silent at the conference.

A. invited       B. inviting          C. being invited           D. having invited

13、Her parents insisted that she ____ a clever student and ____ a better education.

A. is; should receive  B. be; should receive    C. was; receive    D. should be; received

12、--- Was it 2 am ____ you returned home?

--- No, it was at 11 pm ____ I got home.

A. that; when       B. that; that       C. when; when      D. when; that

11、As we all know, every minute, when made full use of ___ our lessons ,will do good to us students.

A. studying        B. studied        C. being studied      D. to study