22、―Why was he unhappy yesterday?

―A letter from home ______ an attack of homesickness.

      A. set off                       B. set out                       C. set about             D. set up

21、 ―How are you getting along with your new job and your classmates?

― ______.

      A. I can’t tell you                                               B. So far, so good

      C. I’m glad you asked me about it                        D. I’m not getting along with Jane

20、The light will be thrown ______ the cause of cancer by research that is now in progress.

      A. to                             B. upon                         C. in                       D. for

19、When you are reading fast, your eyes will be one or two word groups ahead of ______ your mind is taking in.

      A. one                           B. others                       C. the others            D. the one

18、

It is worth considering what makes “convenience” foods so popular, and ____ better ones of your own.

A. introduces                      B. to introduce                  C. introducing                             D. introduced

17、I’m sorry you’ve been waiting so long, but it’ll still be some time ____ Brian get back.

A. before                   B. since                      C. till                           D. after

16、If you really have to leave during the meeting, you’d better leave ____ the back door.

A. for                     B. by                           C. across                 D. out

15、I feel greatly honored ____ into their society.

A. to welcome                B. welcoming             C. to be welcomed          D. welcomed

13、The companies are working together to create         they hope will be the best means of transport in the 21^st century.

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