Wind is the great maker of waves. There are exceptions, such as the tidal waves, sometimes produces by earthquakes under the sea. But the waves most of us know are produced by winds blowing over the sea.Now before constructing an imaginary life history of a typical wave, we need to know certain physical things about it. A wave has height, from trough (low point)to crest (high point),and it has length—the distance from this crest to that of the following wave. The period of the wave means the time it takes for succeeding crests to pass a fixed point. None of these things stays the same— for all depend upon the depth of the water and many other matters.
The water that makes up a wave does not advance with it across the sea. Each drop of water turns around in a little circle with the passing of the wave, but returns very nearly to its original position. And it is fortunate that this is so, for if the huge masses of water that make up a wave actually moved across the sea, sailing would be impossible.
If we want to find the speed of a wave, we may use the following way:
Speeding=Wavelength×Frequency
Here, wavelength is the distance between two high points (crests), frequency means the number of cycles per second.
41.What causes waves according to the passage?
Earthquakes and nothing else. B. Wind and volcanos.
C. Wind and earthquakes. D. Wind and water.
42.Which of the following is true according to the text?
A. The water of a wave moves away across the sea.
B. The water of a wave remains almost in the same place.
C. The water of a wave goes with the passing of the wave.
D. The length of a wave means the distance between crest and trough.
43.The underlined word “succeeding” means__________.
A. reaching an aim B. doing well C. following after D. taking place
44.If the speed of wave 1 is 100 cm/s, and its frequency 10;and the frequency of wave 2 is 300,while its speed is twice that of wave 1.Which of the following is true?
A. The wave-lengths of the two are equal.
B. The wave-length of wave 1 is 10 times longer than that of Wave 2.
C. The wave-length of wave 2 is longer than that of wave 1.
D. The wave-length of wave 1 is longer than that of wave 2.
完形填空（共20小题；每小题1.5分，满分30分）
阅读下面短文，掌握其大意，然后从各题所给的A、B、C、D四个选项中，选出最佳选项。
Tired and hungry, two boys walked painfully and difficultly into a big city on October 16, on their feet that had just carried them 300 kilometers.
For nine days they lived like old-fashioned travelers, 21 somewhere new to sleep every night as they walked from one place to another. The boys slept in tents and 22 a six-yuan daily plan. “I learned more in those nine days than I had in the last nine years,” said 17-year-old Li Zhao 23 . Li and 15-year-old Li Xuemeng 24 their journey on October 7, with three teachers from an Educational Motivation Research & Service Center. The purpose of the 25 was for the two troubled boys to develop a (an) 26 attitude to school and life.
With two 27 and some instant noodles for the first day, the five 28 mainly along the Highway 107. On the way to the big city, 29 of them visited schools and interviewed 30 people from different walks of life. Both were asked to write about what they 31 during the walk.
“ The two boys need to know about 32 life and learn to get rid of difficulties, so we 33 this program,” explained Du Junpeng. 34 they had tents, they didn’t just 35 anywhere at night. “We had to 36 on people’s kindness for shelter,” said Li Zhao, who admits he used to be self-centered and at first was 37 against the idea of the trip. But the challenge of getting rid of the 38 on the journey has changed him.
“I’m more 39 than before. And now I also believe failure is the mother of 40 ,” he said.
21. A. finding B. hunting C. searching D. inventing
22. A. lived on B. worked on C. carried out D. went on
23. A. anxiously B. luckily C. excitedly D. tiredly
24. A. developed B. separated C. controlled D. started
25. A. study B. trip C. task D. job
26. A. passive B. popular C. different D. active
27. A. tents B. lights C. drinks D. tools
28. A. ran B. drove C. walked D. marched
29. A. both B. none C. either D. some
30. A. famous B. brave C. different D. strange
31. A. covered B. learned C. heard D. recognized
32. A. interesting B. real C. hard D. meaningful
33. A. carried on B. cared about C. took over D. worked out
34. A. Although B. If only C. As though D. Since
35. A. sleep B. adventure C. move D. tour
36. A. get B. depend C. take D. turn
37. A. hardly B. heavily C. strongly D. secretly
38. A. wrongs B. problems C. difficulties D. fears
39. A. sociable B. particular C. common D. formal
40. A. success B. victory C. hope D. aim
The Pyramid, which ________ thousands of years ago, ______ Egypt.
A. dates from; is belonging to B. dates back to; belongs to
C. dated from; is belonged to D. dated back to; belongs to
Many peasants in the north go to the south _____ much money.
A. make an attempt at making B. in attempts to make
C. making an attempt to making D. attempt to make
As a role model, I don’t think most people can imagine what it’s like ____that close every minute of the day.
A. to be watched B. watched C. watching D. to watch
. We should be able to ________ enough money for your ticket.
A. dig up B. look up C. take up D. set up
