20．---My God! 　When did you get the door ________?

---Last week．

A．to paint　 　　B．painted　　 　　　 C．painting　 　　　　　　 D．to be painted

19．I do every single bit of housework ______ my husband Bob just does the dishes now and then．

A．since　　　　 　　　 B．while　　 　　　　 C．when　　　 　　　　　 D．as

18．The Great Wall, _____ to be the longest wall in the world, runs across China like a huge dragon．

A．saying　　　　 　　 B．to say　　　 　 C．said　　 　　　　　　　 D．being said

17．It is widely believed among bioengineers _____ it will be possible to create life under laboratory conditions．

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

16．Teaching ___ child to cook will improve many of ___ skills that he or she will need later in life．

A．/; the　　　　 　 B．a; the　　　 　　　　 C．a ; /　　　 　　　　　　 D．the; a

15. -Rather than ___ on a crowded bus, he always prefers ___ a bicycle.

A. ride; to ride　　 　B. riding; ride　 　　　C. ride; ride 　　　　D. to ride; Riding

14. Kate didn’t come yesterday, or you ________ her.

　　 A. would see　 　　B. were to see　　　　 C. had seen 　　　　　D. might have seen