四六级

　　英语六级听力改革后，考试题型变化较大，包括长对话、听力篇章和讲座，大家平时要有针对性的加强练习。今天小编给大家提供的是英语六级听力mp3在线听第一套讲座1，希望对大家更好地进行2017年6月英语六级备考有帮助。

英语六级听力mp3在线听第一套讲座1.mp3

　　Now listen to the following recording andanswer questions 16 to 19.

　　16

　　A.There are different kinds of sound waves.

　　B.Different people have different abilities of sense.

　　C.There are different kinds of seismic waves.

　　D.The travelling speed of waves differs greatly.

　　17

　　A.They travel deep inside the earth.

　　B.They travel slow inside the earth.

　　C.They are too small to be felt.

　　D.They travel too fast to be felt.

　　18

　　A.The preliminary waves.

　　B.The secondary waves.

　　C.The surface waves.

　　D.The body waves.

　　19

　　A.The love waves.

　　B.The primary waves.

　　C.The surface waves.

　　D.The Rayleigh wave.

　　Moderator: Good morning, class. Today Professor Liu will give us a lecture about earthquakes. Welcome.

　　Professor Liu: Thank you. As you know, some earthquakes are not powerful enough to be felt on the Earth's surface while in others, people can, indeed, feel the earth shaking. And of course, there might be violent movement, often with catastrophic results. What we feel during an earthquake or huge explosion are a series of waves called seismic waves.

　　In an earthquake, you might initially feel some minor trembling, then perhaps violent shaking, and then some more tremors. (16) The reason why you feel these different types of movement is because there are different kinds of seismic waves. There are two major types of seismic waves: body waves and surface waves.

　　The waves that you feel first are body waves. These mainly travel deep through the Earth's interior rather than at the surface. Some of them travel very fast, and that's why you feel them first. (17) But because they travel deep inside the Earth, they're felt only as tremors. There are two types of body waves. The first type of body wave is the P wave or primary wave. It's the fastest kind of seismic wave. These waves can move through any type of material, including rock and fluids. Because of this and because of their speed, these waves are the first to reach the Earth's surface. You likely won't even hear or feel these waves, but animals may hear them. They're not strong enough to cause significant damage. The other type of body wave is the S wave or secondary wave. Because S waves travel at half the speed of P waves, you won't feel them in the beginning.

　　Unlike body waves, surface waves move at or near the Earth's surface. These waves are similar to ripples on water. (18) They are usually the most destructive type of seismic wave because of their lower frequency, larger amplitude, and longer duration. There are two types of surface waves. The first kind of surface wave is called a love wave. It's the fastest surface wave. The other kind of surface wave is the Rayleigh wave. It rolls along the ground just like a wave rolls across a lake or an ocean. As a result, it moves the ground up and down and side to side in the same direction that the wave is moving. (19) Most of the shaking felt from an earthquake is due to the Rayleigh wave, which can be much larger than the other waves. They are slower than body waves, and sometimes cars might appear to be moving up and down with these waves.

　　16. Why do we feel different types of movement in an earthquake?

　　17. Why do we feel body waves only as tremors?

　　18. What is the most destructive type of seismic wave?

　　19. Which seismic wave brings us shaking felt from an earthquake?

　　参考答案：

　　【小题16】C

　　【小题17】A

　　【小题18】C

　　【小题19】D

　　习题解析：

　　【小题1】讲座中刘教授明确提到The reason why you feel these different types of movement is because there are different kinds of seismic waves.由此可知，在地震时，人们之所以能感觉到不同类型的震动是由于有不同种类的地震波，故选C。

　　【小题2】听力原文中提到But because they travel deep inside the Earth, they're felt only as tremors.此处的they指代的就是上文提到的体波。由此可知，由于体波在地球深处传播，所以人们只感觉到轻微的摇晃，故选A。

　　【小题3】听力原文在提到表面波和水面的涟漪相似之后，紧接着提到They are usually the most destructive type of seismic wave because of their lower frequency, larger amplitude, and longer duration. 指出表面波通常是破坏力最大的一种地震波，因为它的频率更低，振幅更大，持续的时间也更长。故选C。

　　【小题4】听力原文中提到Most of the shaking felt from an earthquake is due to the Rayleigh wave.由此可知，在地震中我们感觉到的大部分震动都是由于瑞利波造成的，故选D。

　　以上就是英语六级听力mp3在线听第一套讲座1的全部内容，祝大家2017年6月英语六级考试顺利通关！

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