19. We found the ground ____ snow.

A.cover with 　　　　B. is covered with　 C.was covered with　 D. was covering with

18. The guide said that the dinosaur eggs ____ about 95 million years ago.

lay　　　　 B. were lay　 C. laid　　 D. were laid

17. Mary ___ an English song in her room last night.

A.was heard to sing 　B. is heard to sing 　C.was heard singing 　D. is heard singing

16.Mary ___ some songs in her room in the morning.

A.heard sing　 B. heard to sing　 C. was heard sing　 D. is heard to sing

15.Nothing can stop us ___ English.

A.learn　　　　 B. learning　 C. learned　 D. learns

14.We are always kept ____.

to smoking　 B. on smoking　 C. from smoking　 D. off smoking

13.They ___ to help the farmers with the harvest last autumn.

asked　　　 B. asking 　C. to ask　　　 D. were asked

12. In the past 10 years, China ____ up many man-made satellites.

A.has been sent　 B. has sent　 　C. was sent　　　　　 D. sent

11.Three quarters of the messages _____ by telegraph.

Was sent　 B. were sent 　　C. Sent　　　 D. send

10.This pair of scissors ___ in China.

A.Make　　　 B. made　 C. is made 　D. are made