完形填空(共20 小题; 每小题1分, 满分20分)
阅读下面短文，掌握其大意,然后从31—50各题所给的四个选项A、B、C和D中，选出一个最佳选项。
The books in David’s schoolbag felt like bricks as he ran down the street. What he wanted to do was to play basketball with Eric,  31  his mother told him he would have to return his sister’s books to the library first.
He had  32  set foot in a library and he wasn’t about to do so today. He would just  33  the books in the outside return box. But there was a  34  ; it was locked. He went into the building, only a few minutes  35  closing time. He put the books into the return box. And after a brief  36  in the toilet, he would be on his way to the playground to  37  Eric.
David stepped out of the toilet and stopped in  38  — the library lights were off! The place was  39 . The doors had been shut. They  40  be opened from the inside, he was trapped(被困) — in a library!
He tried to  41  a telephone call, but was unable to  42 . What’s more, the pay phones were on the outside of the building.   43  the sun began to set, he searched for a light and found it.  44 he could see. David wrote on a piece of paper: “  45  ! I’m TRAPPED inside!” and stuck it to the glass door.  46 , someone passing by would see it.
He was surprised to discover that this place was not so unpleasant,  47  . Rows and rows of shelves held books, videos and music. He saw a book about Michael Jordan and took it off the shelf. He settled into a chair and started to  48  . He knew he had to  49  , but now, that didn’t seem to be such a  50  thing.
31. A. but        B. because      C. or           D. since
32. A. ever       B. nearly       C. never        D. often
33. A. pass       B. drop         C. carry        D. take
34. A. problem    B. mistake       C. case         D. question
35. A. during      B. after          C. over         D. before
36. A. rest       B. break          C. walk        D. stop
37. A. visit       B. meet           C. catch        D. greet
38. A. delight    B. anger          C. surprise     D. eagerness
39. A. lonely    B. empty            C. noisy       D. crowded
40. A. wouldn’t    B. shouldn’t      C. couldn’t      D. needn’t
41. A. make      B. fix             C. use         D. pick
42. A. get on     B. get up         C. get through   D. get in
43. A. If        B. As             C. Though     D. Until
44. A. On time     B. Now and then    C. By the way  D. At last
45. A. Come      B. Help           C. Hello       D. Sorry
46. A. Surely     B. Thankfully     C. Truly         D. Gradually
47. A. at most     B. after all        C. in short       D. as usual
48. A. watch     B. paly           C. read         D. write
49. A. wait     B. stand           C. sleep         D. work
50. A. bad      B. cool            C. strange        D. nice