请认真阅读下面短文，从短文后各题所给的A、B、C、D四个选项中，选出最佳选项，并在答题卡上将该项涂黑。

　　Every Sunday morning I take a light walking around a park near my home. There's a lake 36 in one corner of the park. Each time I 37 by this lake, I see the same elderly woman sitting at the water's 38 with a small metal cage sitting beside her.

　　This past Sunday my 39 got the best of me, so l stopped jogging and walked 40 to her. 41 I got closer, I realized that the metal cage was 42 a small trap. There were three turtles, unharmed, slowly walking around the base of the trap. She had a fourth turtle in her lap 43 she was 44 scrubbing（擦洗） with a spongy brush.

　　"Hello," I said, "If you don't mind my 45 , I'd love to know what you're doing with these turtles."

She smiled. "I'm cleaning off their shells." she replied, " 46 on a turtle's shell, like algae or scum, 47 the turtle's ability to absorb heat and impedes its ability to swim. It can also 48 and weaken the shell over time."

　　She went on, "I spend a couple of hours each Sunday morning, relaxing by this lake and helping these little guys out. It's my own 49 way of making a difference."

　　"But don't most freshwater turtles live their whole lives with algae and scum 50 from their shells?" I asked.

　　"Yep, 51 , they do." she replied.

　　"Well then, don't you think your time could be better spent? And 99% of these turtles don't have kind people like you to help them clean off their shells. So, no 52 ... but how exactly are your localized 53 here truly making a difference?"

　　The woman giggled aloud.

　　She then 54 at the turtle in her lap, scrubbed off the last piece of algae from its shell, and said, "Sweetie, if this little guy 55 talk, he'd tell you I just made all the difference in the world."

36. A. being located B. locating C. located D. having located

37. A. reach B. hike C. wander D. jog

38. A. surface B. bottom C. position D. edge

39. A. tension B. curiosity C. passion D. caution

40. A. over B. down C. up D. around

41. A. Until B. While C. As D. After

42. A. in effect B. in return C. in chaos D. in particular

43. A. that B. where C. which D. what

44. A. attentively B. gradually C. aggressively D. punctually

45. A. request B. permission C. reservation D. nosiness

46. A. Something B. Anything C. Nothing D. Everything

47. A. broadens B. strengthens C. lowers D. enlarges

48. A. weather B. address C. choke D. resist

49. A. rigid B. unique C. explicit D. desperate

50. A. attached B. tied C. hanging D. pinned

51. A. fortunately B. sadly C. basically D. absolutely

52. A. wonder B. problem C. offense D. excuse

53. A. contributions B. efforts C. sacrifices D. arrangements