英语听力文摘 English Digest 166、Why Mountains Stop Growing

　　If you live up in the mountains, understanding the continually shifting landscape can mean survival.
Mountains are continually shifting. Erosion wears mountains down, but active mountain ranges are also continuously rising. And here’s the interesting thing: despite this, once mountains reach a certain height, they achieve a state of equilibrium¹. It may sound weird², but they rise without getting any taller.
You see, mountain ranges form in places where tectonic plates meet–those are the thick sheets of rigid³ rock that cover the earth’s surface. When one tectonic plate slides beneath the other, the parts of it that are scraped off pile up in buckling⁴ folds to form mountains.
Of course, we’re talking geological time here, which is measured in tens of thousands of years. So one question geologists⁵ are investigating is which forces counteract⁶ the shifting and colliding of the tectonic plates and enable still- active mountain ranges to level off at a certain height.
Erosion is caused by many factors, like weather and rivers carving⁷ into the mountains. Also, as mountains get higher, they get steeper, and the greater the slope, the more sediment⁸ ends up sliding down into the oceans instead of accumulating on the mountains themselves.
The big question is what role each of these factors plays in maintaining the height of mountain ranges. And that’s where the debate comes in– and it’s a tough one.

1 equilibrium   

n.平衡，均衡，相称，均势，平静

参考例句：

• Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
• This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。

2 weird   

adj.古怪的，离奇的；怪诞的，神秘而可怕的

参考例句：

• From his weird behaviour,he seems a bit of an oddity.从他不寻常的行为看来，他好像有点怪。
• His weird clothes really gas me.他的怪衣裳简直笑死人。

3 rigid   

adj.严格的，死板的；刚硬的，僵硬的

参考例句：

• She became as rigid as adamant.她变得如顽石般的固执。
• The examination was so rigid that nearly all aspirants were ruled out.考试很严，几乎所有的考生都被淘汰了。

4 buckling   

扣住

参考例句：

• A door slammed in the house and a man came out buckling his belt. 房子里的一扇门砰地关上，一个男子边扣腰带边走了出来。
• The periodic buckling leaves the fibre in a waved conformation. 周期性的弯折在纤维中造成波形构成。

5 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。

6 counteract   

vt.对…起反作用，对抗，抵消

参考例句：

• The doctor gave him some medicine to counteract the effect of the poison.医生给他些药解毒。
• Our work calls for mutual support.We shouldn't counteract each other's efforts.工作要互相支持，不要互相拆台。

7 carving   

n.雕刻品，雕花

参考例句：

• All the furniture in the room had much carving.房间里所有的家具上都有许多雕刻。
• He acquired the craft of wood carving in his native town.他在老家学会了木雕手艺。

8 sediment   

n.沉淀，沉渣，沉积(物)

参考例句：

• The sediment settled and the water was clear.杂质沉淀后，水变清了。
• Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。