题目

以下说法中正确的是（    ） A.波的衍射现象必须具备一定的条件，否则不可能发生衍射现象 B.要观察到水波明显的衍射现象，必须使狭缝的宽度远大于水波波长 C.波长越长的波，越容易发生衍射 D.“闻其声不见其人”，是声波的衍射现象 答案：CD 解析:衍射是波特有的现象，即任何波都会发生衍射现象，只不过存在明显与不明显的差别而已，只有当障碍物或孔的尺寸跟波长差不多或者比波长更小时，才会观察到明显的衍射现象.“闻其声不见其人” 是声波的衍射现象.所以C、D正确. 第三部分：阅读理解 第一节（共15小题；每小题2分，满分30分） 阅读下列短文，从每题所给的四个选项（A、B、C和D）中选出最佳选项，并在答题卡上将该项涂黑。 A man once said how useless it was to put advertisements in the newspaper. “Last week,” he said, “my umbrella was stolen from a London church. As it was a present, I spent twice its worth in advertising, but didn’t get it back.”  “How did you write your advertisement?” asked one of the listeners, a merchant.  “Here it is,” said the man, taking out of his pocket a slip cut from a newspaper. The other man took it and read, “Lost from the City Church last Sunday evening, a black silk umbrella. The gentleman who finds it will receive ten shillings on leaving it at No. 10 Broad Street.”  “Now,” said the merchant, “I often advertise, and find that it pays me well. But the way in which an advertisement is expressed is of extreme importance. Let us try for your umbrella again, and if it fails, I'll buy you a new one.” The merchant then took a slip of paper out of his pocket and wrote: “If the man who was seen to take an umbrella from the City Church last Sunday evening doesn’t wish to get into trouble, he will return the umbrella to No.10 Broad Street. He is well known.” This appeared in the newspaper, and on the following morning, the man was astonished when he opened the front door. In the doorway lay at least twelve umbrellas of all sizes and colors, and his own was among them. Many of them had notes fastened to them saying that they had been taken by mistake, and begging the loser not to say anything about the matter. 56. What is an advertisement? _______________. A. A news item.                                 B. Public opinions. C. One way to voice one’s view.   D. A public announcement on papers, TV, etc. 57. The result of the first advertisement was that ______________. A. the man got his umbrella back B. the man wasted some money advertising C. nobody found the missing umbrella D. the umbrella was found somewhere near the church 58. The merchant suggested that the man should _______________. A. buy a new umbrella                        B. go on looking for his umbrella C. write another and better advertisement     D. report the police 59. “If it fails, I’ll buy you a new one,” suggested that the merchant_______________. A. was quite sure of success                 B. wanted to buy him a new umbrella C. didn’t know what to do                          D. was rich enough to buy one 60. The story is mainly about _________________. A. a useless advertisement         B. how to make an effective advertisement C. how the man lost and found his umbrella D. what the merchant did for the umbrella owner