10．Solid passes sound very well．Try holding a wooden stick against part of a machine，and place your ears against the stick．The movement of the ball-bearings（滾珠軸承） can be clearly heard．This is a good way of finding the exact source of trouble in a motorcar engine which sounds as if it is wrong and yet gives no information of where the trouble is．
It is probably a good thing that sound cannot travel through a vacuum（真空），for we are thus limited to earth-made sounds．The violent disturbances which are seen sometimes in the sun，for example，may affect our magnetism（磁力） and our radio．They do not affect our ears，which is a very good thing for our peace of mind．
If we have used our eyes and ears，we may have realized that sound takes time to travel through the air．The sound of thunder nearly always follows the lightning flash although they happen at exactly the same time．And the appearance of white cloud above a distant ship or train tells us，before anything is heard，that its whistle has sounded．Just how fast does sound travel through the air？
The speed of sound in the air at ordinary temperature is about 100feet per second，which is about one mile in five seconds or about 700miles per hour．The speed of sound increases slightly with a rise in temperature and falls with a decrease in temperature； it is not affected by the pressure of the air．
24．We never hear anything that happens on the sunA．
A．because of the vacuum between the earth and the sun
B．because we are only used to earth-made sound
C．because of the distance between the earth and the sun
D．because we are likely to enjoy our peace of mind
25．According to the passage，how fast does sound travel through the air at ordinary temperature？C
A．About 700meters per minute．
B．About 1，100miles per hour．
C．About 60，000feet per minute．
D．About one kilometer in five seconds．
26．How do temperature and pressure affect the speed of sound？D
A．The speed of sound increase with a rise in pressure．
B．The speed of sound decrease with a rise in temperature．
C．The speed of sound increase in lower temperature and greater pressure．
D．The speed of sound decreases with a fall in temperature．
27．The underlined sentence in the second paragraph means"D"．
A．thus we can hear anything but the sound made by the earth
B．we can thus hear the sound from both the earth and space
C．thus we can hardly hear any sound because of the limit of the earth
D．thus we can only hear the sound made on the earth，not the sound coming from the outside．
分析 文章講述了聲音在空氣中的傳播是受溫度的 影響的，隨著溫度上升而增加，溫度降低而減少，但在真空中是不能傳播的．
解答 24-27 ACDD
24．A 推理題．根據(jù)It is probably a good thing that sound cannot travel through a vacuum（真空），這句話可知，聲音不能通過真空傳播，故有些東西是聽不到的，故選A．
25．C 細(xì)節(jié)題．通過文章The speed of sound in the air at ordinary temperature is about 100feet per second可知，聲音在空氣中每秒100英尺，故每分鐘傳播60，000feet，故選C．
26．D 推理題．根據(jù)最后一段The speed of sound increases slightly with a rise in temperature and falls with a decrease in temperature聲音傳播的速度隨著溫度的增加而增加，相反，隨著溫度下降而降低，故選D．
27．D 推理題．根據(jù)前面的句子It is probably a good thing that sound cannot travel through a vacuum可知，在真空中聲音不能傳播，所有我們只能聽到地球上的聲音，故選D．
點評 本文是人生感悟類閱讀理解．這類題材是高考�？嫉膬�(nèi)容，它注重考查考生整體理解文章大意的能力，在做題時要結(jié)合題干以及上下文做出正確的選擇．
