2、由原子构成的物质：金属、稀有气体、金刚石、石墨等物质

1、由分子构成的物质：例如水、二氧化碳、氢气、氧气等物质

When Dunstan Cass left Silas Marner, the cottage was only a hundred meters away. He was walking home from the village, where he had　 　36 　to buy what he needed 　　37　 　his next day’s work. His legs were tired, but he felt almost happy. He was looking forward to　 38　 , when he would bring out his gold. Tonight he had an extra reason to hurry home. He was going to eat hot meat, which was 　39　 　for him. And it would 　40　 him nothing, because someone had given him a piece of meat as a present. He had left it 　41　 　over the fire. The door key was needed to hold it safe in place, but Cass was not at all 　42　 　about leaving his gold in the cottage with the door 　43　 . He could not imagine that a thief would　 　44　 　his way through the mist, rain and darkness to the little cottage by the quarry ( 采石场 ).

When he reached his cottage and opened the door, he did not notice 　45 　　anything was different. He 　46　 　his wet coat, and pushed the meat 　47　 　the fire. 　　48　 　he was warm again, he began to think about his gold. It seemed a long time to wait until after supper, when he usually brought out coins to look at.　 　49　 　he decided to bring out his gold immediately, while the meat was still cooking.

But when he 　50　 　the floorboards near the loom, and saw the 　51　 　hole, he did not understand 　52　 . His heart beat violently as his trembling hands felt all round the hole. There was 　53　 ! he put his hands to his head and tried to think. Had he put his gold in a different place, and forgotten about it? He 　54　 　every corner of this small cottage, until he could not pretend to himself any more. He had to accept the truth --- his gold had been 　55　 !

36. A. arrived　　　 B. been　　 C. left　　　　　　 D. gone

37. A. to　　　　　　　 B. in　　　 C. for　　　　　　　 D. with

38. A. holiday　 　 B. gold　　　 C. supper-time　　　 D. meat

39. A. ordinary　　 B. unusual　 C. normal　　　　　 D. common

40. A. pay　　　　　 B. spend　　 C. take　　　　　　 D. cost

41. A. boiling　 　 B. cooking　　 C. smoking　　　　　 D. making

42. A. interesting　　　 B. worried　 C. interested　　　 D. worrying

43. A. unlocked B. uncovered　 C. discovered　 　 D. locked

44. A. go　　　 B. lead　　　　 C. find　　　　　　 D. lose

45.A.whether　　　　 B. that　　 C. because　　　　　 D. as

46.A. turned off　　　　 B. threw into　　　 C. threw off　　　　 D. got off

47.A. away from　　 B. farther on　　　 C. on to　　　　　　 D. closer to

48.A. As soon as　　 　 B. As well as 　 C. No sooner　 D. As long as

49.A. But　　　 B. As　　　　　 　 C. So　　　　　　 D. For

50.A. took down　　 B. took after　　　 C. took over　　　　 D. took up

51.A. dark　　　　　 B. empty　　　　 C. small　　　　　　 D. deep

52.A. at last　　　　　 B. at once　　　 C. at most　　　 D. at least

53.A. everything　　　　 B. something　　 C. nothing　　　 D. anything

54.A. searched　 B. searched for C. looked into　　　 D. found

55.A. gone　　　 　 B. missed　　 C. lost　　　　　　 D. stolen

35. - What about having a picnic this weekend?

　 -________. The weather may not be fine.

A. It depends. B. It doesn’t make sense. C. That’s all right. D. I’m glad to hear that.