托福听力短文 II-12-3

(WA) The winds of a tornado¹ are the most violent and destructive ones on Earth. Any of you who have seen one knows very well how frightening and powerful they are. What's interesting about them is that scientists don't actually know exactly why tornadoes² occur.

We do know, however, what happens when tornadoes are formed. As you remember, a front occurs when cool, dry air from the north meets warm, humid air coming from the south (from the Gulf³ of Mexico, for tornadoes in the United States). Where these air masses meet, a narrow zone of storm clouds develops, and thunderstorms, and sometimes tornadoes, occur.

How is this violent weather produced? Well, a mass of warm, humid air rises very rapidly. As it rises, more warm air rushes in to replace it. This inrushing air also rises, and in some cases, especially when there is extreme thermal⁴ instability, begins to rotate. When this happens, the rotating air forms a tornado.

Even if you've seen tornadoes only in movies, you know that they can demolish⁵ buildings in seconds. This is possible because when a tornado passes over a house, it sucks up air from around the house and so the air pressure outside the house drops rapidly. Inside, pressure remains⁶ the same. So, air pressure inside is greater than air pressure outside. The result is that the building explodes outward. Next, we'll talk a little bit about how new technological⁷ developments are being used to try to predict tornadoes.

1 tornado   

n.飓风，龙卷风

参考例句：

• A tornado whirled into the town last week.龙卷风上周袭击了这座城市。
• The approaching tornado struck awe in our hearts.正在逼近的龙卷风使我们惊恐万分。

2 tornadoes   

n.龙卷风，旋风( tornado的名词复数 )

参考例句：

• Tornadoes, severe earthquakes, and plagues create wide spread havoc. 龙卷风、大地震和瘟疫成普遍的毁坏。 来自互联网
• Meteorologists are at odds over the working of tornadoes. 气象学者对龙卷风的运动方式看法不一。 来自互联网

3 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

4 thermal   

adj.热的，由热造成的；保暖的

参考例句：

• They will build another thermal power station.他们要另外建一座热能发电站。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

5 demolish   

v.拆毁(建筑物等)，推翻(计划、制度等)

参考例句：

• They're going to demolish that old building.他们将拆毁那座旧建筑物。
• He was helping to demolish an underground garage when part of the roof collapsed.他当时正在帮忙拆除一个地下汽车库，屋顶的一部份突然倒塌。

6 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

7 technological   

adj.技术的；工艺的

参考例句：

• A successful company must keep up with the pace of technological change.一家成功的公司必须得跟上技术变革的步伐。
• Today,the pace of life is increasing with technological advancements.当今， 随着科技进步，生活节奏不断增快。