2021年江苏专转本（英语）真题试卷_13.docx

本文格式为Word版，下载可任意编辑 PAGE 1 PAGE 1 2021年江苏专转本（英语）真题试卷 一、1.  1.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 interval 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 by 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 rage of flight, in other words) , the device was called radio directing and ranging , and from the initials the word radar was coined. Sound waves reflected from a hill can be used to estimate the______.  A．height of the hill B．speed of soundC．distance to the hillD．intensity of sound 2.  Practical application of this principle resulted in______.  A．new electronic instruments for planes B．a radio directing and ranging deviceC．new radio sets for RAF bombersD．an electronic detecting device 3.  Radar enabled the English to______.  A．detect German planes on their way to London B．direct the outnumbered RAF planes effectivelyC．confuse German bomber pilotsD．both A and B 4.  It can be inferred from the passage that______.  A．light waves could be used in a device similar to radar B．radar was a practical application of a well-known principleC．radar gready increased the ef