10 the train came to an abrupt stop， making us wonder where we were

　　a an uncertain

　　b a slow

　　c an unexpected

　　d a smooth

　　11 almost all economists agree that nations， gain by trading with one another.

　　a work

　　b profit

　　c rely

　　d prove

　　12 the conference explored the possibility of closer trade links.

　　a denied

　　b investigated

　　c stressed

　　d created

　　13 the chemical is deadly to rats but safe to cattle

　　a fatal

　　b hateful

　　c good

　　d useful

　　14 during his lifetime he was able to accumulate quite a fortune.

　　a control

　　b spend

　　c collect

　　d exchange

　　15 its impolite to cut in when two persons are holding a conversation

　　a leave

　　b talk loudly

　　c stand up

　　d interrupt

　　答案：1. c 2. c 3. c 4. c 5. a6. c 7. d 8. b 9. d 10. c11. b 12. b 13. a 14. c 15. d