20．According to a new study by a British university, learning　　　 second language can lead to

　　　 increase in your brain power.

　　　 A．a ;the　　　　　　　　　 B．不填; the　　　　　　 C．a ;an　　　　　　　　　 D．the ;不填

19．-Has he finished writing his essay?

　　　 -No. He　　　 on it when I went to see him this morning.

　　　 A．worked　　　　　　　 B．was working　　　　 C．had worked　　　　 D．is working

18．Finding her car stolen,　　　　 .

　　　 A．a policeman was asked to help　　　　　　　 B．the area was searched thoroughly

　　　 C．it was looked for everywhere　　　　　　　　 D．she hurried to a policeman for help

17．He got lost and spent hours looking for the station, and 　　　　　it was past midnight by the time he got home.

　　　 A．besides　　　　　　　　 B．anyway　　　　　　　 C．somehow　　　　　　 D．however

16．-Jenny took the 8:00 bus to Shanghai this morning.

　　　 -Really? She 　　　　the 9:00 train. It’s much more comfortable and safer to travel by

train.

　　　 A．could have taken　 B．should take 　　　　 C．must have taken　 D．can take

15．Farmers now　　　　 more government help not only of money but also of science and technology on farming.

　　　 A．call on　　　　　　　　 B．call for 　　　　　　　 C．stick to　　　　　　　 D．live on

14．They had wanted to charge $ 5,000 for the car,　　　　 we managed to bring the price down.

　　　 A．but　　　　　　　　　　 B．so　　　　　　　　　　　 C．when　　　　　　　　　 D．since

13．It was in time of danger　　　　 he made the final decision　　　　 they should send more doctors there.

　　　 A．where ;that　　　　　 B．when; which　　　　 C．where ;what　　　　 D．that ;that