一些民间谚语常蕴含着丰富的物理知识，下面四句谚语中对应的物理知识正确的是（ ）
A．潭清疑水浅--光的反射现象
B．一个巴掌拍不响--声音不能在固体中传播
C．人多力量大--杠杆原理
D．磨刀不误砍柴工--减小受力面积，增大压强
A、潭清疑水浅，是由于光从水中射入空气中，在水面处发生光的折射而产生的现象，故A错误；
B、一个巴掌拍不响，是因为只有一个物体，没有另一个物体，力就不会产生，说明力是物体对物体的作用，故B错误；
C、人多力量大是指人数多了，产生的合力就大．而杠杆是一种简单机械，它的原理是动力×动力臂=阻力×阻力臂，所以人多力量大和杠杆原理没有丝毫的联系，故C错误；
D、磨刀不误砍柴工是在压力一定时，减小受力面积增大压强，故D正确．
故选D．
阅读下面的短文，掌握其大意，然后从41-60各题所给的四个选项（A、B、C和D）中，选出最佳选项。） I was on a bus one March evening. The driver didn’t 41 to start the bus soon because it was not yet 42 . A middle-aged woman got on. Tired and sad, she told her story 43 not to anyone in particular. On her way to the station, half of her 44 was stolen. The other half was hidden under her blouse, so she 45 still had some left. A few minutes later, she stopped crying, but still looked 46 . When all the seats were taken, the driver started the engine. The conductor began to collect fares(车费). When she came to an old man in worn-out（破旧的）clothes, he 47 that he had spent all his money when he had accidentally got on a wrong bus and now he was trying to go home. On hearing this, she ordered the old man to 48 the bus. The old man was almost in tears as he 49 her to let him take the bus home. The driver took the conductor’s side(站在某人一边) and repeated the conductor’s 50 . The woman was watching the incident. 51 the driver and the conductor raised their voices at the old man, she interfered(干预). “Stop 52 him! Can’t you see he’s only trying to get home?” “He doesn’t have any money! ” the driver 53 . “Well, that’s no 54 to throw him off the bus,” she insisted. Then she reached inside her blouse, look out her 55 money, and handed it to the conductor. “Here’s his fare and mine. Just stop giving him a 56 time.” All heads turned to the woman. “It’s only money,” she shrugged（耸肩）. She rode the rest of the way home 57 a happy smile, with the money she’d lost earlier 58 . On the road of life, the help of strangers can 59 our loads（负担）and lift our spirits. How much sweeter the 60 will be when we make it a little smoother for others!
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