25、－I’m so tired, working all morning on the farm.

－Why not take a rest, then?

－__________.

A．Because I can’t afford it                              B．Maybe I should

C．I don’t know                                              D．Sorry, I can’t tell it

24、New technology ____ to make sure that the cars, taxis, buses and trains we use _____ the air.

A．is used; not pollute                                      B．has used; is not polluted

C．is being used; do not pollute                         D．has been used; to pollute

21、There is        Mr. Smith with        good knowledge of Chinese history in our school.

A．a; a   B．the; / C．a; the D．/; a

20、It has been announced that students        remain in their seats until all the papers have been collected.

A．can          B．will           C．shall         D．may

19、The defense lawyer was questioning the old man who was one of the        of the murder committed last month.

A．observers         B．viewers     C．witnesses  D．audiences

18、Look at the price of that bike! It is practically the same as        of a new motorcycle.

A．one          B．this           C．it       D．that

17、With the latest technology        , the productivity in our factory has been greatly increased

A．to bring in        B．to be brought in       C．brought in        D．having brought in