参考答案：

1-5 ABABD 6-10 CDBCD

11-15 DBBCA 16-20 ADBCA

21-25 ACACD

26. Is that my computer?

27. The telephone is not mine.

28. It's black.

29. No, it isn't.

30. Two pencils, an eraser and a ruler.

31. Helen's 32. yours 33. pencils 34. me 35. keys

36. teacher 37. Hers 38. library 39. computer 40. ring

41. is 42. color 43. in 44. dictionary 45. spell

46. eraser 47. see 48. pens 49. lost 50. must

51. Are these 52. What about 53. Thank; for 54. ask; for 55. call; at

One possible version:

Lost:

Linda