专升本英语（阅读理解）模拟试卷28
阅读理解
Under proper conditions, sound waves will be reflected from a hillside or other such obstruction. Sound travels at the rate of about one-fifth of a mile per second. If the hill is eleven hundred feet away, it takes two seconds for the sound to travel to the hill and back. Thus, by timing the intervals between a sound and its reflection (the echo), you can estimate the distance to an obstruction.
During World War II the British used a practical application of this principle to detect German planes on their way to bomb London long before the enemy was near the target. They used radio waves instead of sound waves, since radio waves can penetrate fog and clouds. The outnumbered Royal Air Force (RAF) always seemed to the puzzled Germans to be lying in wait at the right time and never to be surprised. It was radio echoes more than anything else that won the Battle of Britain.
Since the radio waves were used to tell the direction in which to send the RAF planes and the distance to send them (their range of flight, in other words) , the device was called radio directing and ranging, and from the initials the word radar was coined.
1.Sound waves reflected from a hill can be used to estimate the______.(C)
A. height of the hill
B. speed of sound
C. distance to the hill
D. intensity of sound
解析：文章第一段最后一句说通过对声音和回音之间的间隔进行计时，可以算出与障碍物之间的距离，故选C。
2.The estimate is based on the______.(C)
A. direction of the hill
B. accepted speed of sound
C. interval between sound and echo
D. both B and C
解析：根据第一段最后一句话Thus，by timing the interval between a sound and its reflection(the echo)，you can estimate the distance to an obstruction，可知C正确。
3.Practical application of this principle resulted in______.(B)
A. new electronic instruments for planes
B. a radio directing and ranging device
C. new radio sets for RAF bombers
D. an electronic detecting device
解析：根据文章最后一句话the device was called radio directing and ranging，and from the initials the word radar was coined，可知B正确。
4.Radar enabled the English to______.(D)
A. detect German planes on their way to London
B. direct the outnumbered RAF planes effectively
C. confuse German bomber pilots
D. both A and B
解析：文章第二段提到在第二次世界大战中，英国人利用无线电波可以侦查出德国飞机的位置，而且那些数量占多数的皇家空军常常会对德军造成一定的困惑，第三段提到那些皇家空军是由那些无线电波指控的。故A项和B项都正确，所以选D。
5.The British used radio waves because they______.(C)
A. were more exact than sound waves
B. could not be detected
C. could penetrate fog and clouds
D. were easier to use than sound waves
解析：根据第二段中They used radio waves instead of sound waves，since radio waves can penetrate fog and clouds，故选C。
A rapid means of long-distance transportation became a necessity for the United States as settlement(新拓居地)spread ever farther westward. The early trains were impractical curiosities , and for a long time the railroad companies met with troublesome mechanical problems. The most serious ones were the construction of rails able to bear the load, and the development of safe, effective stopping system. Once these were solved, the railroad was established as the best means of land transportation. By 1860 there were thousands of miles of railroads crossing the eastern mountain ranges and reaching westward to the M
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