小站备考
托福
托福听力
Official47听力真题

托福official47听力lecture4 the role of wind原文解析+翻译音频

展开
Tip:单击查看句义;划选/双击查生词

[00:00.00]NARRATOR: Listen to part of a lecture in a meteorology class.
[00:04.38]MALE PROFESSOR: Now, Earth's atmosphere is sort of like a giant weather machine, right? [00:08.98]With air and water being its key components. [00:11.96]A machine powered by energy from the Sun. [00:15.36]So, we need to consider the role that air, or, more specifically, wind, plays in this machine.[00:22.99]So wind is really nothing more than moving air, right?
[00:26.80]Now as air is heated, and becomes warmer, it expands, it becomes less dense. [00:32.08]When air in a particular area is heated, you get a concentration of warm air, an area of low pressure. [00:39.60]Uh, likewise, when you get a concentration of cold air, that air's gonna be very dense, so it's gonna create an area of high pressure. [00:48.90]If you have an area of high pressure next to an area of low pressure, the colder, high pressure air will start moving toward the area of low pressure, right? [00:59.87]And the warmer air will move away, rising above the cooler air. [01:04.78]Okay? Uh, yes, Linda?
[01:07.42]FEMALE STUDENT: So wind is actually generated by the Sun?
[01:10.50]MALE PROFESSOR: Well, Earth's rotation plays a role, and there’re other factors, and we'll come back to all that, [01:15.91]but principally, yes. [01:18.32]The Sun creates the temperature differential that creates the areas of high pressure and low pressure that create wind.
[01:25.73]FEMALE STUDENT: Um, I don’t get what …how it causes a temperature differential…
[01:30.96]MALE PROFESSOR: Right. Good. This'll take us to the role of wind in the climate. [01:35.71]The key is that the Sun warms up different parts of Earth at different rates, and to different degrees. [01:43.39]Uh for example, at, uh, at sunrise the land heats up faster than the ocean… [01:50.65]that’s why you get morning sea breezes. [01:53.42]The air over the water heats more slowly than air over land, so during the early morning it's cooler and denser than air over land, so it moves in toward land -- a sea breeze.
[02:07.37]Uh, what else? Um, the Sun's energy is more intense near the equator than it is near the poles. So you've got masses of warmer air over the equatorial regions [02:19.86]and masses of cooler air over polar regions [02:23.75]and these masses are constantly interacting with each other, which is critically important for Earth's climate.
[02:30.39]Uh, one result of these interactions is that equatorial air masses move away from the equator. And in the process, those equatorial winds actually take heat away from the equator and transfer it to some cooler part of Earth. [02:47.52]And by redistributing this energy–the Sun's energy, really–winds play a critical role in maintaining a temperature balance from the poles to the equator.
[02:58.81]Now winds also help Earth maintain its balance in another way: by transporting water from one part of Earth to another. [03:09.44]Water is contained in the air in the form of vapor–mostly through evaporation, mostly from the oceans–[03:17.38]and so when the air moves, it carries the vapor with it to some other parts of Earth, where it can deposit it as rain, or snow, some other form of precipitation.
[03:29.08]Uh actually, the transfer of heat and water by way of the wind are very closely related… [03:36.92]because a primary way that heat energy is transferred by wind is mediated by the process of evaporation. [03:44.91]What happens is that a certain amount of heat energy is required to convert liquid water into vapor. [03:52.12]So when water evaporates from the ocean, it takes energy to convert that water into a gaseous form, into water vapor. [04:01.40]But that heat energy–that conversion energy–doesn't raise the temperature of the water vapor, or of the air. It’s just stored in the water vapor. [04:12.13]Then later, when the water vapor converts back to liquid water, that energy is released.
[04:19.58]So: when water evaporates, energy's taken from the ocean, and it's stored in the water vapor, in the air. [04:29.48]Then the air–the wind–transports the water vapor to some other part of Earth. [04:35.67]Then the water vapor converts back into liquid water–[04:40.06]it rains, in other words–[04:41.86]and the heat energy that was stored in the water vapor is released into the new environment. Okay?
[04:49.18]So the transfer of heat and the transfer of water are very closely related. [04:55.08]And what's the primary vehicle for this transfer? [04:58.63]The wind. So wind is a critical element in the redistribution of both the Sun's energy and Earth's water.

1.What is the lecture mainly about?

你的答案:
正确答案:C
题目解析:
 后才能查看题目解析,还没有账号? 马上注册
听力文章首先介绍风的形成原因是因为温差,接着介绍温差原因是陆地海洋变热速度不同以及地区接受热量不同,然后介绍风可以转移水因此可以转移分配热量,最后强调风对于调节地球气候至关重要,对应选项C中:The role of wind in regulating Earth’s climate。

学习页面

Medi

terr

anean

加强 + 政府 + 名词后缀

加强的政府——管理

原文例句

加入生词

本文生词 0

色块区域是你收藏过的生词;

查询次数越多,颜色越深哦~

显示文中生词

登录后才能收藏生词哦,现在登录注册>

本文重点词 45

文中加粗单词为本文重点词;

根据词频与核心词范围精心挑选,托福考试必掌握词汇。

显示文中重点词
学习本文词汇

文中划选/双击的生词、加粗重点词已收纳至词盒

可随时点击词盒查看哦~

只有在词句精学模式下才能开启词盒功能哦~

我知道了

词盒
收藏
笔记
我的笔记
5000
保存
反馈