三、阅读下面短文，撑握其大意，然后从16—35各题所给的四个选项（A、B、C和D）中，选出最佳选项。（每小题1分，满分20分）
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 toliet, he would be on his way to the playground to 37 Eric.
David stepped out of the toliet 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 worse, 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