20．Every boy and every girl as well as some teachers who______ to visit the museum ______ asked to be at the school gate before 6:30 in the morning.

　　　 A．are; are　　　　 B．are; is　　　　　　　　 C．is; is　　　　　　 D．is; are

19．Jerry is such a lazy man ______ nobody wants to work with______.

　　　 A．as; him　　　　 B．that; 不填　　　　　 C．whom; him　　　 D．as; 不填

18．-______when has the country been open to international trade?

　　 -1978, I suppose.

　　　 A．Since　　　　　 B．In　　　　　　　　　　　 C．From　　　 　　　　 D．After

17．You are required to find out ______ the differences between American English and British English lie.

　　　 A．what　　　　 　　 B．how　　　　　　　　　　 C．where　　　　　 D．which

16．Believe it or not, it is ______ that causes your illness.

　　　 A．because of your being overweight　　　　 B．because you are overweight

　　　 C．you are so overweight　　　　　　　　　　　　　 D．your being overweight

15．“Can you read?”, Mary said ______ to the notice.

　　　 A．angrily pointing　 B．and point angrily　

　　　 C．angrily pointed　 　　　　　　　　　　　　　　　 D．and angrily pointing