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1、全国英语六级考试听力摸底练习 Every man is his own worst enemy.以下是为大家搜索的全国听力摸底练习，希望能给大家带来帮助!更多精彩内容请及时关注我们! Y: Why does salt melt ice? 为什么食盐能让冰块融化? D: It lowers the melting and freezing point of water. 是因为食盐将水的熔点和冰点降低了。 Y: Oh,OK.Wait,I dont get it. Doesnt that mean the salt make ice colder? 等一下，我不明白。这就意味着食盐让冰的温度变得更
2、低吗? D: Let me explain.Pure water freezes at thirty-two degrees Fahrenheit,right? At that temperature we can say that the rate of freezing is the same as the rate of melting. 我解释一下。纯洁水的冰点是32华氏度，对吧?这个温度既是冰点也是熔点。 Y: So in other words, at waters freezing point theres a sort of equilibrium between freezi
3、ng and melting. 也就是说，水的冰点就是结冰和融化的平衡。 D: Right.Throwing salt on ice upsets the balance. 是的。在冰上洒盐扰乱了这种平衡。 Y: Upsets it how? 怎么打乱的呢? D: The salt dissolves into the liquid water, which means that some of the water molecules are replaced by salt. Since there are now fewer liquid water molecules to be cap
4、tured and frozen by the ice, the rate of freezing drops. 盐溶解在水中，就是说一局部水分子被盐取代了。既然结冰的液态水分子减少了，冰点自然降低了。 Y: I think I get it.And Since the rate of melting stays the same, theres more melting going on than freezing. And so the ice melts. 我明白了。水的熔点不变，融化的水分子比结冰的多，所以冰块就融化了。 D: Right. 对。 Y: Interesting. 很有趣
5、。 D: In fact, anything that dissolves in water will do the trick. You could pour sugar on ice and it willmelt. But I guess since salt is cheaper its used more often. 其实，任何溶于水的物质都可以使冰融化。把糖洒在冰上，冰也会融化。但是我想也许由于盐比拟廉价，所以经常被使用。 A: Whats the biggest mag ever? 终究什么是最大的磁体? B: Well, thats a great question. Wel
6、l, for starters youd have to mention whoppers like the hybrid mag at the National High Magic Field Lab in Tallahassee, Florida.This mag weighs thirty-four tons and stands twenty-two feet tall.Giant mags in hospitals, physics labs, and other facilities help in cutting edge research. However, even a m
7、ag the size of a building cant pete with a mag the size of a pla. 嗯，问得好。对于初学者来说，不得不提一下那些庞然大物，比方佛罗里达塔拉哈西的国家高磁场实验室的混合磁体。这块磁铁重34吨，立起来有22英尺高。医院，物理实验室和其他设备里的巨型磁体对尖端研究有帮助。然而，即使是一块建筑物大小的磁体也不能和一块行星大小的磁体相匹敌。 A: A mag the size of a pla? 一块行星大小的磁体? B: The Earth itself is a mag! Researchers think its the effect
8、 of convection currents in our plas molten interior that causes the entire Earth to behave as one gigantic mag, with a North and South Pole.Whenever you look at a pass, what youre doing is reading the magic field of the pla on which you are standing. 地球本身就是一块磁体。研究者们认为，是地球内部熔岩里对流流的作用使得整个地球像个拥有南北磁极的巨型
9、磁体一样运转。每当你看着指南针的时候，你所做的就是读取你所在行星的磁场。 A: So that must be the biggest mag than anywhere. 所以那就是最大的磁体咯。 B: Yet, even a mag the size of a pla cant pete with a mag the size of a star. 但是，即使是行星大小的磁体也不能和恒星大小的磁体相匹敌。 A: A star? 恒星? B: what about the sun? The sun is a mag. In this case, the magic field is prob
10、ably generated by swirling plasma. Magic storms on the sun are powerful enough to have an effect on satellites and munication systems all the way here on Earth. 比方说太阳?太阳是一块磁体。假假设这样，磁场可能是由旋动的等离子产生的。太阳上的磁暴威力足够强大，可以对人造卫星和地球上通信系统的各个方面产生影响。 A: So is that? 那就是最大的了? B: Not even close. There are things in space that put all of these mags to shame. 还差得远呢。宇宙中还有更多让这些磁体相形见绌的事物呢。 A: Super mag in space? What are they? 宇宙中的超强磁体?是些什么呢? B: Next time. 下次再说吧。
