托福听力短文 I-05-3

(man) I'm glad you brought up the question of our investigations¹ into the makeup² of the Earth's interior. In fact --- since this is the topic of your reading assignment for next time --- let me spend these last few minutes of class talking about it. There were several important discoveries in the early part of this century that helped geologists⁴ develop a more accurate picture of the Earth's interior.

The first key discovery had to do with seismic⁵ waves --- remember they are the vibrations⁶ caused by earthquakes. Well, scientists found that they traveled thousands of miles through the Earth's interior. This finding enabled geologists to study the inner parts of the Earth. You see, these studies revealed that these vibrations were of two types: compression --- or P --- waves and shear⁷ --- or S --- waves. And researchers found that P waves travel through both liquids and solids, while S waves travel only through solid matter.

In 1906 a British geologist³ discovered that P waves slowed down at a certain depth but kept traveling deeper. On the other hand, S waves either disappeared or were reflected back, so he concluded that depth marked the boundary between a solid mantle⁸ and a liquid core. Three years later another boundary was discovered --- that between the mantle and the Earth's crust.

There's still a lot to be learned about the Earth. For instance, geologists know that the core is hot. Evidence of this is the molten lava⁹ that flows out of volcanoes. But we're still not sure what the source of the heat is.

1 investigations   

（正式的）调查( investigation的名词复数 )； 侦查； 科学研究； 学术研究

参考例句：

• His investigations were intensive and thorough but revealed nothing. 他进行了深入彻底的调查，但没有发现什么。
• He often sent them out to make investigations. 他常常派他们出去作调查。

2 makeup   

n.组织；性格；化装品

参考例句：

• Those who failed the exam take a makeup exam.这次考试不及格的人必须参加补考。
• Do you think her beauty could makeup for her stupidity?你认为她的美丽能弥补她的愚蠢吗？

3 geologist   

n.地质学家

参考例句：

• The geologist found many uncovered fossils in the valley.在那山谷里，地质学家发现了许多裸露的化石。
• He was a geologist,rated by his cronies as the best in the business.他是一位地质学家，被他的老朋友们看做是这门行当中最好的一位。

4 geologists   

地质学家，地质学者( geologist的名词复数 )

参考例句：

• Geologists uncovered the hidden riches. 地质学家发现了地下的宝藏。
• Geologists study the structure of the rocks. 地质学家研究岩石结构。

5 seismic   

a.地震的，地震强度的

参考例句：

• Earthquakes produce two types of seismic waves.地震产生两种地震波。
• The latest seismic activity was also felt in northern Kenya.肯尼亚北部也感觉到了最近的地震活动。

6 vibrations   

n.摆动( vibration的名词复数 )；震动；感受；（偏离平衡位置的）一次性往复振动

参考例句：

• We could feel the vibrations from the trucks passing outside. 我们可以感到外面卡车经过时的颤动。
• I am drawn to that girl; I get good vibrations from her. 我被那女孩吸引住了，她使我产生良好的感觉。 来自《简明英汉词典》

7 shear   

n.修剪，剪下的东西，羊的一岁；vt.剪掉，割，剥夺；vi.修剪，切割，剥夺，穿越

参考例句：

• Every spring they shear off the sheep's wool and sell it.每年春天他们都要剪下羊毛去卖。
• In the Hebrides they shear their sheep later than anywhere else.在赫伯里兹，剪羊毛的时间比其他任何地方都要晚。

8 mantle   

n.斗篷，覆罩之物，罩子；v.罩住，覆盖，脸红

参考例句：

• The earth had donned her mantle of brightest green.大地披上了苍翠欲滴的绿色斗篷。
• The mountain was covered with a mantle of snow.山上覆盖着一层雪。

9 lava   

n.熔岩，火山岩

参考例句：

• The lava flowed down the sides of the volcano.熔岩沿火山坡面涌流而下。
• His anger spilled out like lava.他的愤怒像火山爆发似的迸发出来。