16. Before the _______ of gunpowder (火药) , men fought with bows and arrows.

　　A) exposure B) invitation C)discovery D) invention

　　17.1 won’t get _______in the quarrel between Tom and Jack.

　　A) involved B) included C) consisted D) contained

　　18. Sherlock Holmes ____ many cases by following the footprints left at the scene of the crime.

　　A) invested B) investigated C) suspected D) suggested

　　19. He ________ himself from the outside world by living in the mountains.

　　A) divided B) prevented C) isolated D) related

　　20. The great ______ today is whether there will be war or peace.

　　A) problem B) difference C) issue D) tissue

　　21. Jenny was always very _________ of her sister’s beauty.

　　A) jealous B) hated C) curious D) pleased

　　222. The two sides agreed on a _____ business venture in which both put up an equal amount of capital(资本).

　　A) joined B) double C) joint D) common

　　23. After suffering such unfair treatment, the child felt there was no _________ in this world.

　　A) fairy B) equality C) justice D) chance

　　24. You must walk slowly if you want your children to ________ you.

　　A) keep in touch B) keep up with C) hold on to D) put up with

　　225. 225. He receives so many letters every day that sometimes he ______ sufficient time to read all of them properly.

　　A) lacks B) spends C) costs D) takes

　　226. John and James are brothers. The former is a teacher; the ________ is an engineer.

　　A) later B) last C) latter D) second

　　27. The Americans and Russians have _____ many rockets into space.

　　A) landed B) launched C) initiated D) attacked

　　28. The gardens are beautifully __________.

　　A) laid aside B) laid down C) laid off D) laid out

　　29. As a result of a bomb explosion, oil has _________ out from the tanker.

　　A) lacked B) leaked C) left D) dropped

　　30. She ________ her elbows on her knees and cupped her chin in her hands.

　　A) depended B) relied C) counted D) leaned

　　参考答案：

　　1. B 2. A 3. D 4. B 5. C 6. C 7. B 8. D 9. C 10. B

　　21.C 12. A 13. A 14.C 15.B 16.D 17. A 18.B 19.C 20.C

　　21. A 22. C 23. C 24. B 25. A 26. C 27. B 28. D 29. B 30. D