『新东方在线托福听力』为托福考生准备了ETS托福TPO/Official 46 Lec 4听力练习：What does the professor mainly discuss?原文题目答案解析，TPO/Official 46 Lec 4听力原文范文音频翻译。

托福TPO/Official 46 Lec 4听力原文What does the professor mainly discuss?【新东方在线】

旁白：请听材料科学的一部分讲座。

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

教授：那么，当我们谈论铜的用途时，我们想到的第一件事是什么？Tammy？

Professor: So what's the first thing that comes to mind when we talk about uses for copper? Tammy?

学生：一分钱。它是由铜制成的。

但是现在一个一分钱硬币值什么呢？

But what's a one cent coin worth these days?

就像你去商店，给收银员5美元，买一些花费4美元98美分的东西，你会得到2分钱找零，但2分钱买不了什么。

Like if you go to the store and give the cashier 5 dollars for something that costs 4 dollars 98 cents, you'll get 2 cents back, but 2 cents does not buy much.

从购买力来说，一分钱的价值已经变得如此之低，以至于事实上有了一个这样的举动，就是从美国货币当中消除一分硬币。

The value of the penny in terms of what it'll buy has gotten so low that there's actually a move afoot to eliminate the coin from US currency.

正如Tammy所暗示的，一分钱看起来像是固体铜。

As Tammy implied, the penny looks like it's solid copper.

当它是新的时候，它是红橙色的，有一个明亮的金属光泽，但这只是电镀铜。

It is reddish orange with a bright metallic luster when it's new, but that's just the copper plating.

In actuality, it is almost 98 percent zinc.

但是，嗯……鉴于这两种金属的价值上涨，每一分硬币现在要花费1.7美分来制作。

But, um, given the rising value of both these metals, each penny now costs about 1.7 cents to produce.

所以它产生了所谓的负铸币税。

So it generates what is called negative Seigniorage.

负铸币税是指铸造硬币的成本大于硬币的面值。

Negative seigniorage is when the cost of minting a coin is more than the coin's face value.

虽然一分钱产生了相当多的负铸币税，但有人担心，如果它被淘汰，我们将需要更多的5美分镍，因为更多的商人可能开始以5美分的价格增量开始定价，如4美元95美分等。

Even though the penny generates quite a bit of negative seigniorage, there is concern that if it's eliminated, we'll need more nickels, because more merchants might start setting prices in five-cent increments, 4 dollars 95 cents and so on.

所以我们需要一个可靠的五分钱可以被经济地铸造。

So we need a trusty five-cent piece that can be minted economically.

但是，五分镍币的负铸币税甚至比便士更糟。 每一块五分镍币都花费美国10美分铸币。

But the nickel's negative seigniorage is even worse than the pennies. Each nickel costs the US mint 10 cents to produce.

此外，我们有些人非常喜欢便士，无论什么原因，可能怀旧，还有那些收藏家。

Also, some of us are pretty attached to pennies for whatever reason, nostalgia, and then those collectors.

而人们如果在人行道上看到一分钱，便会拾起来，认为：这是我的幸运日！

And people, if they see a penny on the sidewalk, they'll pick it up and think: it is my lucky day!

另一种情况是，没有便士，商人，可能会把价格定成整数到甚至五美元，而不是4.98。

Another scenario is that, without pennies, merchants, instead of charging 4.98, might round up the price to an even five dollars.

So consumer goods would become slightly more expensive.

但另一方面，一些现金交易对消费者来说更方便。

But on the other hand, some cash transactions would be more convenient for consumers.

正如我所说，如果消除了便士，政府将会省钱。

And as I said, the government would save money if pennies were eliminated.

学生：但是，如果美国政府停止购买铜来制造便士的话，铜工业不会在财政上受到影响吗？

Student: But wouldn't the copper industry suffer financially if the US government stopped buying copper to make pennies?

教授：但是便士里实际包含多少铜呢？

Professor: But how much copper do pennies actually contain?

学生：多少……哦，明白了，对。

教授：那么，当你想到铜时还能想到什么其它的呢？

Professor: So what else comes to mind when you think about copper?

学生：我知道铜可以塑造成各种各样的东西：板材，管材，我表弟的房子有一个铜屋顶。

Student: I know that copper can be shaped into all sorts of things: sheets, tubing, and my cousin's house has a copper roof.

教授：是的，像金和银，铜也是极具延展性的，但它不是一种贵金属，远没有金或银昂贵。

Professor: Yes, like gold and silver, copper is extremely malleable, but it's not a precious metal, it's far less expensive than gold or silver.

它也是一个极好的电导体，因此你可以将它拉成线，用于电器甚至汽车发动机。

It's also a superb conductor of electricity so you can stretch it into wires which go into appliances and even car motors.

铜还具有优良的合金化性能，它……你知道，当它与其它金属结合的时候。

Copper also has superior alloying properties, it's... you know, when it's combined with other metals.

例如，你们中有多少人演奏铜管乐器，如小号或长号？

For instance, how many of you play a brass instrument, like a trumpet or a trombone?

Well, brass is an alloy of copper and zinc.

如果你的长号是纯铜或纯锌，它不会听起来像黄铜长号那么动听。

If your trombone was made of pure copper or pure zinc, it wouldn't sound nearly as beautiful as a brass trombone.

另一种合金，铜和镍的组合，抗腐蚀。

Another alloy, a combination of copper and nickel, resists corrosion.

它不生锈，即使长期暴露于水。

It does not rust, even with prolonged exposure to water.

学生：但是在纽约港的自由女神像呢？

Student: But what about the Statue of Liberty in New York Harbor?

它是由纯铜制成，但它变成绿色。

It's made of pure copper, but it turned green.

教授：间接地。如果铜暴露在潮湿的空气中，其颜色从红橙色变成红棕色。

Professor: Indirectly. If copper's exposed to damp air, its color changes from reddish orange to reddish brown.

但是，随着时间的推移，一个绿色的膜形成，称为铜绿，铜绿实际上用于停止任何进一步的腐蚀。

But in time, a green film, called a patina, forms and the patina actually serves to halt any further corrosion.

这是为什么船体由铜-镍合金制成的一个原因。

It is one reason that ship hulls are made of copper-nickel alloys.

这些合金使藤壶粘附也变得困难。

These alloys are also hard for the barnacles to stick to.

如果这些小贝类附着在船体上，会产生阻力，使船只减速。

If these little shellfish adhere to the hull of a ship, it produces drag, slowing the vessel down.

铜也是太阳能加热单元和海水淡化工厂中使用的关键材料，它将在社会中发挥越来越重要的作用。

Copper's also a key material used in solar heating units and in water desalination plants, which will play increasingly important roles in society.

总结一下：如果你可以接受这种说法的话，那么假如你是一名矿工，你不会因为便士的消失而损失任何睡眠（因为担忧失业而感到焦虑）。

Bottom line: if you are a copper miner, you won't lose any sleep should the penny get. If you'll excuse the expression, pinched out of existence.

What arguments in favor of keeping the penny in circulation does the professor emphasize?

What does the professor say about the negative seigniorage of the nickel?

Why does the professor mention the trumpet and trombone?

What does the professor imply about the green patina that sometimes appears on copper?

Listen to part of a lecture in the materials science class. 
M: So what's the first thing that comes to mind when we talk about uses for copper, Tammy? 
W: Penny? It’s made of copper. 
M: Okay, good one. But what's the one cent point worse these days? You might get back change like if you go to the store and get the cashier five dollars for something that costs $4.98, you get two cents back. But your sense doesn't buy much. The value of the penny in terms of what her buy is got so low that is actually a move afoot to eliminate coins from US currency, but is more to it. As Tammy applied depending looks like, it's solid copper is reddish orange with a bright metallic luster when it's new, but that's just the copper plating. The penny is not solid copper. In actuality it's almost 98% zinc, but…um, given the rising value of both these metals, each penny now costs about 1.7 cents to produce, so it generates what's called negative seigniorage. 
Negative seigniorage is when the cost of meeting the coin is more than the queen's face value. Even though the penny generates quite a bit of native seigniorage, there is concerned that if it is eliminated will need more nickels because more merchants would start setting prices in five cent increments, $4.95 and so on. So we need a trusty five cent piece they can be minted economically, but the Nichols negative seigniorage is even worse than the pennies. 
Each nickel costing US mint $0.10 to produce. Also, some of us are pretty attached to pennies for whatever reason. The seller and those collectors and people if they see a penny on the sidewalk, they’ll pick it up and think it's my lucky day. Another scenario is that without pennies, merchants set up charging for 98 might round up the price $25. So consumer goods would become slightly more expensive, but on the other hand some cash transactions would be more convenient for consumers. And as I said the government would save money if penny were eliminated. 
W: But wouldn’t the copper industry suffer financially if the US government stopped buying copper make pennies? 
M: But how much copper do pennies actually contain? 
W: How much? OH…got it! Right! 
M: So what else comes to mind anything about copper? What else is copper used for? 
W: I know the copper can be shaped to all sorts of things, sheets, tubing…My cousins house is a copper roof. 
M: Yes. Like gold and silver copper's extremely valuable, but it's not a precious metal. It's far less expensive than gold or silver. It's also a superb conductor of electricity. So you can stretch into wires, going to appliances and even car motors. Copper also has superior alloying properties. It's, you know, when it's combined with other metals. For instance, how many of you play a brass instrument like a trumpet or trombone? Well, brass is an alloy of copper and zinc. If your trombone made of pure copper or pure zinc, it wouldn’t sound as beautiful as a brass trombone. Another alloy, accomplish copper and nickel resist corrosion, it doesn't rust even with prolonged exposure to water. 
W: But what about the Statue of Liberty in New York Harbor? It's made of pure copper but it turned green. Isn't that a sign of corrosion? 
M: Indirectly, if coppers exposed to damp air its color changes from reddish orange to reddish-brown, but in time the green film called the patina forms. And the patina actually search the halt any further corrosion. It's one reason that ship holes are made of copper nickel alloys. These alloys are also hard for barnacles to stick, too. If these little shellfish is here for the whole ship produces drag slowing the vessel down. Coppers also a key material used in solar heating units and water desalination plants which is playing increasingly important roles in society. Bottom line, if you're a Coppermine or you won't lose any sleep should the penny get, if you excuse the expression pinched out of existence.

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