Carbon Nanotubes托福聽力原文翻譯及問題答案

Carbon Nanotubes托福聽力原文翻譯及問題答案

一、Carbon Nanotubes托福聽力原文：

NARRATOR:Listen to part of a lecture in a structural engineering class.MALE PROFESSOR:Today,let's begin to look at structural engineering in the Space Age.Uh,new problems...new possibilities mean we can think in new ways...find radically different approaches.So let's consider,uh—well,What would you say is the biggest obstacle today to putting structures,equipment,people uh—anything,really—into space?FEMALE STUDENT:Well,the cost,right?MALE PROFESSOR:Exactly.I mean,just taking the space shuttle up and back one time is hugely expensive.Uh,why?FEMALE STUDENT:I-I guess a lot of it is for fuel,right?To—to get the rocket going fast enough...MALE PROFESSOR:OK...Fast enough to...?FEMALE STUDENT:To,uh,escape Earth's gravity.MALE PROFESSOR:Good.So we are burning up an enormous amount of fuel at every launch,just to get the rocket up to what's known as"escape velocity".Now,escape velocity is around 11 kilometers a second,pretty fast.But do we really have to go this fast?FEMALE STUDENT:Well...yeah!I mean,how else can you,um,escape?I mean,that's the whole point of escape velocity,right?Otherwise gravity will pull you back down to the Earth....

MALE PROFESSOR:Actually,that's a common misconception.Escape velocity is simply the speed of an object that's,uh,let's say,shot out of a cannon,the minimum initial speed so that the object could later escape Earth's gravity on its own.But that's just if there's no additional force being applied.If you keep on supplying force to the object,keep on pushing it upward.It could pull away from Earth's gravity at any speed.FEMALE STUDENT:Even really slow?So you're saying,like,if you had a ladder tall enough,you could just climb into space?MALE PROFESSOR:Yeah—uh,well,theoretically.I mean,I can see some practical problems with the ladder example.Uh,like you might get just a little bit tired out after the first few thousand kilometers or so,uh,especially with all the oxygen tanks you'd have to be hauling up with you!MALE PROFESSOR:No.I was thinking more along the lines of an elevator...FEMALE STUDENT:Wait,you're serious?MALE PROFESSOR:Sure.An elevator.That's a new idea to most of us,but in fact it's been around for over a century.If we could power such an elevator with solar energy,we could simply rise up into space--for a fraction of the cost of a trip by rocket or shuttle.FEMALE STUDENT:But wait,elevators don't just rise up.They have to hang on some kind of wire or track or something.MALE PROFESSOR:Uh,true—and for decades that's exactly what's prevented the idea from being feasible,or even just taken seriously: Um,where do we find a material strong enough,yet light weight enough,to act as a cable or track. I mean,we're talking 36,000 kilometers here—and the strain on the cable would be more than most materials could bear.

But a new material developed recently has a tensile strength higher than diamond,yet it's much more flexible. I'm talking about carbon nanotubes.

FEMALE STUDENT:OK.I've read something about carbon nanotubes.They are strong,alright,but aren't they just very short little cylinders in shape?MALE PROFESSOR:Ah,yes.But these cylinders cling together at a molecular level.You pull out one nanotube or row of nanotubes,and its neighbor's come with it,and their neighbors,and so on.So you could actually draw out a 36,000-kilometer strand or ribbon of nanotubes stronger than steel,but maybe a thousandth the thickness of a human hair.FEMALE STUDENT:OK.Fine.But what's going to hold this ribbon up and keep it reach enough to support an elevator car?MALE PROFESSOR:Well,we definitely have to anchor it at both ends.So what we need is a really tall tower here on the ground right at the equator and a satellite in geostationary orbit around the Earth.There's a reason I mentioned that figure of 36,000 kilometers.That's about how high an object would have to be orbiting straight up from the equator to constantly remain directly above the exact same spot on the rotating planet Earth.So once you are in this geostationary orbit right over the tower,just lower your carbon nanotube cable down from the satellite,tether it to the tower here on Earth.And there you have it!FEMALE STUDENT:So you really think this is a possibility?Like,how soon could it happen?MALE PROFESSOR:Well,the science fiction writer Arthur C.Clarke talked about building a space elevator back in the 1970s.And when someone asked him when he thought this idea might become a reality,his reply was,"Probably about fifty years after everybody quits laughing."

二、Carbon Nanotubes托福聽力中文翻譯：

旁白：請聽結(jié)構(gòu)工程課的一部分講座。男教授：今天，讓我們來看看太空時(shí)代的結(jié)構(gòu)工程。嗯，新的問題…新的可能性意味著我們可以用新的方式思考…找到完全不同的方法。那么，讓我們考慮一下，呃，你認(rèn)為今天在將結(jié)構(gòu)、設(shè)備、人，呃，任何東西真正送入太空方面最大的障礙是什么？女學(xué)生：嗯，成本，對嗎？男教授：沒錯(cuò)。我的意思是，僅僅乘坐航天飛機(jī)往返一次就非常昂貴。為什么？女學(xué)生：我想很多都是燃料，對吧？為了讓火箭飛得足夠快…男教授：好吧…足夠快到。。。？女學(xué)生：為了逃避地球引力。男教授：很好。因此，我們在每次發(fā)射時(shí)都要消耗大量的燃料，以使火箭達(dá)到所謂的“逃逸速度”?，F(xiàn)在，逃逸速度大約是每秒11公里，相當(dāng)快。但我們真的要這么快嗎？女學(xué)生：嗯……是的！我的意思是，你還能怎么逃脫？我的意思是，這就是逃逸速度的全部意義，對嗎？否則，地心引力會(huì)把你拉回到地球。。。。

男教授：事實(shí)上，這是一個(gè)普遍的誤解。逃逸速度就是物體從大炮中射出的速度，最小初始速度，這樣物體就可以自己逃逸地球重力。但這只是如果沒有施加額外的力。如果你繼續(xù)向物體提供力，繼續(xù)向上推動(dòng)它。它可以以任何速度脫離地球引力。女學(xué)生：真的很慢嗎？所以你的意思是，如果你有足夠高的梯子，你可以直接爬到太空中？男教授：是的，嗯，理論上。我的意思是，我可以看到梯子例子的一些實(shí)際問題。呃，就像你在最初的幾千公里后可能會(huì)有點(diǎn)累，呃，尤其是你必須帶著所有的氧氣罐！男教授：不，我想的更多的是電梯……女學(xué)生：等等，你是認(rèn)真的嗎？男教授：當(dāng)然。電梯。對我們大多數(shù)人來說，這是一個(gè)新想法，但事實(shí)上，它已經(jīng)存在了一個(gè)多世紀(jì)。如果我們能用太陽能為這樣的電梯提供動(dòng)力，我們就可以簡單地升入太空——只需花費(fèi)火箭或航天飛機(jī)旅行的一小部分費(fèi)用。女學(xué)生：但是等等，電梯不只是上升。他們必須掛在某種電線或軌道上。男教授：嗯，是的，幾十年來，這正是這個(gè)想法不可行，甚至不被認(rèn)真對待的原因：；嗯，我們在哪里能找到一種足夠堅(jiān)固、重量又足夠輕的材料來充當(dāng)電纜或軌道&nbsp；我的意思是，我們在這里討論36000公里，電纜上的張力將超過大多數(shù)材料所能承受的。

但最近開發(fā)的一種新材料的抗拉強(qiáng)度高于金剛石，但它的柔韌性要高得多&nbsp；我說的是碳納米管。

女學(xué)生：好的，我讀過一些關(guān)于碳納米管的文章。它們很結(jié)實(shí)，好吧，但它們只是形狀很短的小圓柱體嗎？男教授：啊，是的。但這些圓柱體在分子水平上緊密結(jié)合在一起。你拔出一根納米管或一排納米管，它的鄰居和他們的鄰居，等等。所以你實(shí)際上可以拔出一條36000公里長的比鋼更堅(jiān)固的納米管，但可能是人類頭發(fā)厚度的千分之一。女學(xué)生：好的，很好。但是，什么能支撐住這條帶子，讓它夠到支撐電梯轎廂的高度呢？男教授：好吧，我們一定要把它固定在兩端。所以我們需要的是一個(gè)非常高的塔，在赤道的地面上，一顆衛(wèi)星在地球靜止軌道上。我提到36000公里是有原因的。這是關(guān)于一個(gè)物體必須從赤道垂直向上運(yùn)行的高度，才能一直保持在旋轉(zhuǎn)行星地球上的同一點(diǎn)的正上方。所以，一旦你在塔樓上方的地球靜止軌道上，只要把你的碳納米管電纜從衛(wèi)星上放下來，把它拴在地球上的塔樓上。你就在那里！女學(xué)生：那么你真的認(rèn)為這是可能的？比如，這會(huì)發(fā)生多久？男教授：科幻作家亞瑟·C·克拉克（Arthur C.Clarke）早在20世紀(jì)70年代就談到過建造太空電梯。當(dāng)有人問他這個(gè)想法何時(shí)會(huì)成為現(xiàn)實(shí)時(shí)，他的回答是：“大概是在大家都不再笑了50年后?！?/p>

三、Carbon Nanotubes托福聽力問題：

Q1:1.What is the main purpose of the lecture?

A.To help students understand what is required to launch a satellite

B.To describe new materials now being used to explore space

C.To describe a potential technology for space exploration

D.To show how ideas from science fiction often develop into actual technologies

Q2:2.Why does the student mention climbing a ladder?

A.To demonstrate his familiarity with certain new types of technology

B.To make sure he understands the point the professor is making

C.To raise an objection to the professor's claims about escape velocity

D.To provide a humorous example for the other students'amusement

Q3:3.What does the professor imply about using carbon nanotubes in the development of space elevators？

A.Current technology is good enough to make space elevators even without nanotubes.

B.We do not yet have the technology to bind nanotubes together in a ribbon.

C.Nanotube cables would not be rigid enough to support an elevator car.

D.Nanotubes are the kinds of materials that will be needed if space elevators are ever to be built.

Q4:4.According to the professor,what is the significance of having a satellite in orbit about 36,000 kilometers above Earth's surface?

A.This is the physical limit of the length that a carbon nanotube cable could reach.

B.A satellite orbiting at this height can remain directly above on location on Earth.

C.Earth's gravitational field is too weak to hold a satellite in orbit at higher altitudes.

D.The distance around Earth's equator is approximately 36,000 kilometers.

Q5:5.Why does the professor mention the writer Arthur C.Clarke?

A.To use a comment made by Clarke as a way of answering a student's question.

B.To familiarize students with Clarke's ideas on space engineering.

C.To cite a prominent opponent of the idea of space elevators.

D.To point out that Clarke wrote about carbon nanotube technology long before it became a reality.

Q6:6.What can be inferred about the professor when he says this?

A.He is enjoying an opportunity to make his students laugh.

B.He is disappointed that none of his students thought of this idea themselves.

C.He wants his students to seriously consider an idea they might find surprising.

D.He has spent a great deal of time researching the idea that he is now presenting.

四、Carbon Nanotubes托福聽力答案：

A1:正確答案：C

A2:正確答案：B

A3:正確答案：D

A4:正確答案：B

A5:正確答案：A

A6:正確答案：C

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