网站导航     在线客服  
全部
2018托福真题解析汇总
学生选择在小站备考:30天 431680名,今日申请152人    备考咨询 >>

【小站原创】TPO6托福听力Lecture4文本+题目+答案解析

2018年01月19日16:01 来源:小站整理
参与(0) 阅读(2623)

托福备考资料免费领取

免费领取
摘要:TPO托福模考软件是目前市面上最好用的托福备考资料了,托福考生一般都会拿TPO来进行托福考试的练习。这里小编将为大家整理了完整理了TPO6托福听力Lecture4文本+题目+答案解析,帮助大家更好的进行托福听力备考

现在大家在进行托福备考时TPO托福模考软件相信是大家用的最多的工具了,对于托福成绩的提升是非常有帮助的。托福听力可以说是整个托福考试当中比较重要的一个部分,如何利用现有资料TPO模考软件来提升大家的托福成绩呢?今天小编在这里整理了TPO6托福听力Lecture 4文本+题目+答案解析来分享给大家,希望对大家托福听力备考有帮助。

TPO6托福模考软件配套资料汇总→→点击进入

【小站原创】TPO6托福听力Lecture4文本+题目+答案解析图1

TPO6托福听力Lecture4原文文本

Narrator: Listen to part of a lecture in an earth science class.

Professor: We’re really just now beginning to understand how quickly drastic climate change can take place. We can see past occurrences of climate change that took place over just a few hundred years.

Take uh… the Sahara Desert in Northern Africa. The Sahara was really different 6,000 years ago. I mean, you wouldn’t call it a tropical paradise or anything, uh…or maybe you would if you think about how today in some parts of the Sahara it…it only rains about once a century. Um… but basically, you had greenery and you had water.

And what I find particularly interesting... amazing really, what really indicates how undesert-like the Sahara was thousands of years ago, was something painted on the rock, prehistoric art – hippopotamuses. As you know hippos need a lot of water and hence? Hence what?

Student: They need to live near a large source of water year around.

Professor: That’s right.

Student: But how is that proof that the Sahara used to be a lot wetter? I mean the people who painted those hippos, well, couldn’t they have seen them on their travels?

Professor: Okay, in principle they could, Karl. But the rock paintings aren’t the only evidence. Beneath the Sahara are huge aquifers, basically a sea of fresh water, that’s perhaps a million years old filtered through rock layers. And…er…and then there is fossilized pollen, from low shrubs and grasses that once grew in the Sahara.

In fact these plants still grow, er…but hundreds of miles away, in more vegetated areas. Anyway, it’s this fossilized pollen along with the aquifers and the rock paintings, these three things are all evidence that the Sahara was once much greener than it is today, that there were hippos and probably elephants and giraffes and so on.

Student: So what happened?

Professor: How did it happen? Well, Now, we’re so used to hearing about how human activities are affecting the climate, right? But that takes the focus away from the natural variations in the earth climate, like the Ice Age, right? The planet was practically covered in ice just a few thousand years ago. Now as far as the Sahara goes, there is some recent literature that points to the migration of the monsoon in that area

Students: Huh?????

Professor: What do I mean? Okay, a monsoon is a seasonal wind that can bring in a large amount of rainfall. Now if the monsoon migrates, well, that means that the rains move to another area, right?

So what caused the monsoon to migrate? Well, the answer is: the dynamics of earth’s motions, the same thing that caused the Ice Age by the way. The earth’s not always the same distance from the sun, and it’s not always tilting toward the sun at the same angle. There are slight variations in these two parameters. They’re gradual variations but their effects can be pretty abrupt. And can cause the climate to change in just a few hundred years.

Student: That’s abrupt?

Professor: Well, yeah, considering that other climate shifts take thousands of years, this one is pretty abrupt. So these changes in the planet’s motions, they caused the climate to change.

But it was also compounded. What the Sahara experienced was uh…a sort of “runaway drying effect”. As I said the monsoon migrated itself, so there was less rain in the Sahara. the land started to get drier, which in turn caused a huge decrease in the amount of vegetation, because vegetationdoesn’t grow as well in dry soil, right?

And then, less vegetation means the soil can’t hold water as well, the soil loses its ability to retainwater when it does rain. So then you have less moisture to help clouds form, nothing to evaporatefor cloud formation. And then the cycle continues, less rain, drier soil, less vegetation, fewer clouds, less rain etc. etc.

Student: But, what about the people who made the rock paintings?

Professor: Good question. No one really knows. But there might be some connections to ancient Egypt.

Student: oh…

At about the same time that the Sahara was becoming a desert…hmm ...5,000 years ago, Egypt really began to flourish out in the Nile River valley. And that’s not that far away. So it’s only logical to hypothesize that a lot of these people migrated to the Nile valley when they realized that this was more than a temporary drought.

And some people take this a step further. And that’s okay, that’s science and they hypothesize that this migration actually provided an important impetus in the development of ancient Egypt. Well, we’ll stay tuned on that.

查看TPO6托福听力Lecture4的题目请进入下一页→→→

更多最新,最in的托福资讯,关注公众号:小站托福(ID:xiaozhantuofu2015)
特别申明:本文内容来源网络,版权归原作者所有,如有侵权请立即与我们联系contactus#zhan.com,我们将及时处理。
感觉茅塞顿开?现在就去练练手吧!
大家都在学

看完这篇文章有何感觉?已经有0人表态,0%的人喜欢

相关文章

【小站原创】TPO40-51题目及答案解析全收录(完整版) 【小站原创】TPO40托福听力Conversation题目... 【小站原创】TPO41托福听力Lecture题目文本及答案... 【小站原创】TPO40托福听力Lecture题目文本及答案... 【小站原创】TPO42托福听力Lecture题目文本及答案... 【小站原创】TPO48托福听力Lecture题目文本及答案... 【小站原创】TPO44托福听力Lecture题目文本及答案... 【小站原创】TPO48托福听力Conversation题目...