托福閱讀材料集錦大全
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托福閱讀材料之天文學(xué)習(xí)題
在托?？荚囍?，天文學(xué)科也從來(lái)都是被重點(diǎn)考察的學(xué)科之一。今天就來(lái)跟大家分享兩道托福TPO?？架浖刑煳膶W(xué)的閱讀題目。
第一道題目來(lái)自于TPO 8 Running Water on Mars
Paragraph 2: Outflow channels are probably relics of catastrophic flooding on Mars long ago. They appear only in equatorial regions and generally do not form extensive interconnected networks. Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains. The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. Judging from the width and depth of the channels, the flow rates must have been truly enormous-perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same times as the northern volcanic plains formed.
Question: According to paragraph 2, all of the following are true of the outflow channels on Mars EXCEPT:
A. They formed at around the same time that volcanic activity was occurring on the northern plains.
B. They are found only on certain parts of the Martian surface.
C. They sometimes empty onto what appear to have once been the wet sands of tidal beaches.
D. They are thought to have carried water northward from the equatorial regions.
解析：題干問(wèn)的是原文關(guān)于“outflow channels”的描述。在真正考試中，把原文閱讀完畢再去和選項(xiàng)比較會(huì)花費(fèi)較多時(shí)間。因此，比較合理的做題順序是，先讀選項(xiàng)，然后拿選項(xiàng)和原文信息去比對(duì)。
A選項(xiàng)說(shuō)的是outflow channel的形成時(shí)間和火山活動(dòng)在北部平原的發(fā)生時(shí)間是相同的。快速瀏覽原文，只有在最后一句提到了它們的形成時(shí)間，說(shuō)大概在30億年前，about引導(dǎo)的時(shí)間狀語(yǔ)很重要，補(bǔ)充說(shuō)明了這一時(shí)間和北部火山平原形成的時(shí)間相同。A正確。
B選項(xiàng)說(shuō)的是火山形成的地點(diǎn)，只在火星表面的特定區(qū)域?？丛模诙?，說(shuō)的是它們只在赤道區(qū)域出現(xiàn)。B也正確。
C選項(xiàng)說(shuō)的是它們有時(shí)候會(huì)流到曾經(jīng)的濕沙地上。原文在提到tidal beaches時(shí)，并沒(méi)有提到這一信息，因此，C選項(xiàng)是不符合原文的。
D選項(xiàng)說(shuō)的是河水從赤道(南)向北流動(dòng)。和原文第三句話吻合：這些河流的走向是從南部高低到北部平原。
因此，本題的正確答案為C項(xiàng)。
第二道題目來(lái)自于 TPO 16 Planets in Our Solar System
Paragraph 4: Other dimensions along which the two groups differ markedly are density and composition. The densities of the terrestrial planets average about 5 times the density of water, whereas the Jovian planets have densities that average only 1.5 times the density of water. One of the outer planets, Saturn, has a density of only 0.7 that of water, which means that Saturn would float in water. Variations in the composition of the planets are largely responsible for the density differences. The substances that make up both group of planets are divided into three groups-gases, rocks, and ices-based on their melting points. The terrestrial planets are mostly rocks: dense rocky and metallic material, with minor amounts of gases. The Jovian planets, on the other hand, contain a large percentage of the gases hydrogen and helium, with varying amounts of ices: mostly water, ammonia, and methane ices.
Question: Paragraph 4 mentions which of the following as a reason why terrestrial planets are dense?
A. They are made up of three groups of substances.
B. They are composed mainly of rocky and metallic materials.
C. They contain more ice than Jovian planets.
D. They contain relatively small amounts of water.
解析：題干問(wèn)的是類地行星密度較大的原因。那我們只需將做題重點(diǎn)鎖定在原文描述“density”的信息上即可。原文中含有density的句子，第一句在說(shuō)類地行星的密度和其他行星的密度比。第二句說(shuō)的是土星密度。第三句說(shuō)到行星結(jié)構(gòu)的不同影響著密度的不同。后面進(jìn)一步闡釋組成行星的物質(zhì)：氣體，巖石以及冰。接著又提到類地行星主要由巖石組成。顯然，這就是它密度大的原因。綜合比較，應(yīng)該選B。
托福閱讀材料之埃及羅塞塔石碑
A Rosetta Stone for a lost language
0:11
I'd like to begin with a thought experiment. Imagine that it's 4,000 years into the future. Civilization as we know it has ceased to exist -- no books, no electronic devices, no Facebook or Twitter. All knowledge of the English language and the English alphabet has been lost. Now imagine archeologistsdigging through the rubble of one of our cities. What might they find? Well perhaps some rectangular pieces of plastic with strange symbols on them. Perhaps some circular pieces of metal. Maybe some cylindrical containers with some symbols on them. And perhaps one archeologist becomes an instant celebrity when she discovers -- buried in the hills somewhere in North America -- massive versions of these same symbols. Now let's ask ourselves, what could such artifacts say about us to people 4,000 years into the future?
1:14
This is no hypothetical question. In fact, this is exactly the kind of question we're faced with when we try to understand the Indus Valley civilization, which existed 4,000 years ago. The Indus civilization was roughly contemporaneous with the much better known Egyptian and the Mesopotamian civilizations,but it was actually much larger than either of these two civilizations. It occupied the area of approximately one million square kilometers, covering what is now Pakistan, Northwestern India and parts of Afghanistan and Iran. Given that it was such a vast civilization, you might expect to find really powerful rulers, kings, and huge monuments glorifying these powerful kings. In fact, what archeologists have found is none of that. They've found small objects such as these.
1:59
Here's an example of one of these objects. Well obviously this is a replica. But who is this person? A king? A god? A priest? Or perhaps an ordinary person like you or me? We don't know. But the Indus people also left behind artifacts with writing on them. Well no, not pieces of plastic, but stone seals, copper tablets, pottery and, surprisingly, one large sign board, which was found buried near the gate of a city. Now we don't know if it says Hollywood, or even Bollywood for that matter. In fact, we don't even know what any of these objects say, and that's because the Indus script is undeciphered. We don't know what any of these symbols mean.
2:44
The symbols are most commonly found on seals. So you see up there one such object. It's the square object with the unicorn-like animal on it. Now that's a magnificent piece of art. So how big do you think that is? Perhaps that big? Or maybe that big? Well let me show you. Here's a replica of one such seal.It's only about one inch by one inch in size -- pretty tiny. So what were these used for? We know that these were used for stamping clay tags that were attached to bundles of goods that were sent from one place to the other. So you know those packing slips you get on your FedEx boxes? These were used to make those kinds of packing slips. You might wonder what these objects contain in terms of their text.Perhaps they're the name of the sender or some information about the goods that are being sent from one place to the other -- we don't know. We need to decipher the script to answer that question.
3:38
Deciphering the script is not just an intellectual puzzle; it's actually become a question that's become deeply intertwined with the politics and the cultural history of South Asia. In fact, the script has become a battleground of sorts between three different groups of people. First, there's a group of people who are very passionate in their belief that the Indus script does not represent a language at all. These people believe that the symbols are very similar to the kind of symbols you find on traffic signs or the emblems you find on shields. There's a second group of people who believe that the Indus script represents an Indo-European language. If you look at a map of India today, you'll see that most of the languages spoken in North India belong to the Indo-European language family. So some people believe that the Indus script represents an ancient Indo-European language such as Sanskrit.
4:28
There's a last group of people who believe that the Indus people were the ancestors of people living in South India today. These people believe that the Indus script represents an ancient form of the Dravidian language family, which is the language family spoken in much of South India today. And the proponents of this theory point to that small pocket of Dravidian-speaking people in the North, actually near Afghanistan, and they say that perhaps, sometime in the past, Dravidian languages were spoken all over India and that this suggests that the Indus civilization is perhaps also Dravidian.
5:03
Which of these hypotheses can be true? We don't know, but perhaps if you deciphered the script, you would be able to answer this question. But deciphering the script is a very challenging task. First, there's no Rosetta Stone. I don't mean the software; I mean an ancient artifact that contains in the same text both a known text and an unknown text. We don't have such an artifact for the Indus script.And furthermore, we don't even know what language they spoke. And to make matters even worse,most of the text that we have are extremely short. So as I showed you, they're usually found on these seals that are very, very tiny.
5:37
And so given these formidable obstacles, one might wonder and worry whether one will ever be able to decipher the Indus script. In the rest of my talk, I'd like to tell you about how I learned to stop worryingand love the challenge posed by the Indus script. I've always been fascinated by the Indus script ever since I read about it in a middle school textbook. And why was I fascinated? Well it's the last major undeciphered script in the ancient world. My career path led me to become a computational neuroscientist, so in my day job, I create computer models of the brain to try to understand how the brain makes predictions, how the brain makes decisions, how the brain learns and so on.
6:15
But in 2007, my path crossed again with the Indus script. That's when I was in India, and I had the wonderful opportunity to meet with some Indian scientists who were using computer models to try to analyze the script. And so it was then that I realized there was an opportunity for me to collaborate with these scientists, and so I jumped at that opportunity. And I'd like to describe some of the results that we have found. Or better yet, let's all collectively decipher. Are you ready?
6:41
The first thing that you need to do when you have an undeciphered script is try to figure out the direction of writing. Here are two texts that contain some symbols on them. Can you tell me if the direction of writing is right to left or left to right? I'll give you a couple of seconds. Okay. Right to left, how many? Okay. Okay. Left to right? Oh, it's almost 50/50. Okay. The answer is: if you look at the left-hand side of the two texts, you'll notice that there's a cramping of signs, and it seems like 4,000 years ago, when the scribe was writing from right to left, they ran out of space. And so they had to cram the sign. One of the signs is also below the text on the top. This suggests the direction of writing was probably from right to left, and so that's one of the first things we know, that directionality is a very key aspect of linguistic scripts. And the Indus script now has this particular property.
7:34
What other properties of language does the script show? Languages contain patterns. If I give you the letter Q and ask you to predict the next letter, what do you think that would be? Most of you said U, which is right. Now if I asked you to predict one more letter, what do you think that would be? Now there's several thoughts. There's E. It could be I. It could be A, but certainly not B, C or D, right? The Indus script also exhibits similar kinds of patterns. There's a lot of text that start with this diamond-shaped symbol. And this in turn tends to be followed by this quotation marks-like symbol. And this is very similar to a Q and U example. This symbol can in turn be followed by these fish-like symbols and some other signs, but never by these other signs at the bottom. And furthermore, there's some signsthat really prefer the end of texts, such as this jar-shaped sign, and this sign, in fact, happens to be the most frequently occurring sign in the script.
8:24
Given such patterns, here was our idea. The idea was to use a computer to learn these patterns, and so we gave the computer the existing texts. And the computer learned a statistical model of which symbols tend to occur together and which symbols tend to follow each other. Given the computer model, we can test the model by essentially quizzing it. So we could deliberately erase some symbols,and we can ask it to predict the missing symbols. Here are some examples. You may regard this as perhaps the most ancient game of Wheel of Fortune.
9:04
What we found was that the computer was successful in 75 percent of the cases in predicting the correct symbol. In the rest of the cases, typically the second best guess or third best guess was the right answer. There's also practical use for this particular procedure. There's a lot of these texts that are damaged. Here's an example of one such text. And we can use the computer model now to try to complete this text and make a best guess prediction. Here's an example of a symbol that was predicted. And this could be really useful as we try to decipher the script by generating more data that we can analyze.
9:36
Now here's one other thing you can do with the computer model. So imagine a monkey sitting at a keyboard. I think you might get a random jumble of letters that looks like this. Such a random jumble of letters is said to have a very high entropy. This is a physics and information theory term. But just imagine it's a really random jumble of letters. How many of you have ever spilled coffee on a keyboard?You might have encountered the stuck-key problem -- so basically the same symbol being repeated over and over again. This kind of a sequence is said to have a very low entropy because there's no variation at all. Language, on the other hand, has an intermediate level of entropy; it's neither too rigid,nor is it too random. What about the Indus script? Here's a graph that plots the entropies of a whole bunch of sequences. At the very top you find the uniformly random sequence, which is a random jumble of letters -- and interestingly, we also find the DNA sequence from the human genome and instrumental music. And both of these are very, very flexible, which is why you find them in the very high range. At the lower end of the scale, you find a rigid sequence, a sequence of all A's, and you also find a computer program, in this case in the language Fortran, which obeys really strict rules. Linguistic scripts occupy the middle range.
10:49
Now what about the Indus script? We found that the Indus script actually falls within the range of the linguistic scripts. When this result was first published, it was highly controversial. There were people who raised a hue and cry, and these people were the ones who believed that the Indus script does not represent language. I even started to get some hate mail. My students said that I should really seriously consider getting some protection. Who'd have thought that deciphering could be a dangerous profession? What does this result really show? It shows that the Indus script shares an important property of language. So, as the old saying goes, if it looks like a linguistic script and it acts like a linguistic script, then perhaps we may have a linguistic script on our hands. What other evidence is there that the script could actually encode language?
11:38
Well linguistic scripts can actually encode multiple languages. So for example, here's the same sentence written in English and the same sentence written in Dutch using the same letters of the alphabet. If you don't know Dutch and you only know English and I give you some words in Dutch,you'll tell me that these words contain some very unusual patterns. Some things are not right, and you'll say these words are probably not English words. The same thing happens in the case of the Indus script. The computer found several texts -- two of them are shown here -- that have very unusual patterns. So for example the first text: there's a doubling of this jar-shaped sign. This sign is the most frequently-occurring sign in the Indus script, and it's only in this text that it occurs as a doubling pair.
12:23
Why is that the case? We went back and looked at where these particular texts were found, and it turns out that they were found very, very far away from the Indus Valley. They were found in present day Iraq and Iran. And why were they found there? What I haven't told you is that the Indus people were very, very enterprising. They used to trade with people pretty far away from where they lived, and so in this case, they were traveling by sea all the way to Mesopotamia, present-day Iraq. And what seems to have happened here is that the Indus traders, the merchants, were using this script to write a foreign language. It's just like our English and Dutch example. And that would explain why we have these strange patterns that are very different from the kinds of patterns you see in the text that are found within the Indus Valley. This suggests that the same script, the Indus script, could be used to write different languages. The results we have so far seem to point to the conclusion that the Indus script probably does represent language.
13:19
If it does represent language, then how do we read the symbols? That's our next big challenge. So you'll notice that many of the symbols look like pictures of humans, of insects, of fishes, of birds. Most ancient scripts use the rebus principle, which is, using pictures to represent words. So as an example, here's a word. Can you write it using pictures? I'll give you a couple seconds. Got it? Okay. Great.Here's my solution. You could use the picture of a bee followed by a picture of a leaf -- and that's "belief," right. There could be other solutions. In the case of the Indus script, the problem is the reverse.You have to figure out the sounds of each of these pictures such that the entire sequence makes sense. So this is just like a crossword puzzle, except that this is the mother of all crossword puzzlesbecause the stakes are so high if you solve it.
14:17
My colleagues, Iravatham Mahadevan and Asko Parpola, have been making some headway on this particular problem. And I'd like to give you a quick example of Parpola's work. Here's a really short text.It contains seven vertical strokes followed by this fish-like sign. And I want to mention that these seals were used for stamping clay tags that were attached to bundles of goods, so it's quite likely that these tags, at least some of them, contain names of merchants. And it turns out that in India there's a long tradition of names being based on horoscopes and star constellations present at the time of birth. In Dravidian languages, the word for fish is "meen" which happens to sound just like the word for star.And so seven stars would stand for "elu meen," which is the Dravidian word for the Big Dipper star constellation. Similarly, there's another sequence of six stars, and that translates to "aru meen," which is the old Dravidian name for the star constellation Pleiades. And finally, there's other combinations,such as this fish sign with something that looks like a roof on top of it. And that could be translated into "mey meen," which is the old Dravidian name for the planet Saturn. So that was pretty exciting. It looks like we're getting somewhere.
15:29
But does this prove that these seals contain Dravidian names based on planets and star constellations?Well not yet. So we have no way of validating these particular readings, but if more and more of these readings start making sense, and if longer and longer sequences appear to be correct, then we know that we are on the right track. Today, we can write a word such as TED in Egyptian hieroglyphics and in cuneiform script, because both of these were deciphered in the 19th century. The decipherment of these two scripts enabled these civilizations to speak to us again directly. The Mayans started speaking to us in the 20th century, but the Indus civilization remains silent.
16:14
Why should we care? The Indus civilization does not belong to just the South Indians or the North Indians or the Pakistanis; it belongs to all of us. These are our ancestors -- yours and mine. They were silenced by an unfortunate accident of history. If we decipher the script, we would enable them to speak to us again. What would they tell us? What would we find out about them? About us? I can't wait to find out.
16:45
Thank you.
16:47
托福閱讀材料之空氣污染問(wèn)題
Air Pollution
Comes From Many Sources
Here's what you need to know about the warming planet, how it's affecting us, and what's at stake.
Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution—some visible, some invisible—that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.
Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years.
Other greenhouse gases include methane—which comes from such sources as swamps and gas emitted by livestock—and chlorofluorocarbons (CFCs), which were used in refrigerants and aerosol propellants until they were banned because of their deteriorating effect on Earth's ozone layer.
Another pollutant associated with climate change is sulfur dioxide, a component of smog. Sulfur dioxide and closely related chemicals are known primarily as a cause of acid rain. But they also reflect light when released in the atmosphere, which keeps sunlight out and causes Earth to cool. Volcanic eruptions can spew massive amounts of sulfur dioxide into the atmosphere, sometimes causing cooling that lasts for years. In fact, volcanoes used to be the main source of atmospheric sulfur dioxide; today people are.
Industrialized countries have worked to reduce levels of sulfur dioxide, smog, and smoke in order to improve people's health. But a result, not predicted until recently, is that the lower sulfur dioxide levels may actually make global warming worse. Just as sulfur dioxide from volcanoes can cool the planet by blocking sunlight, cutting the amount of the compound in the atmosphere lets more sunlight through, warming the Earth. This effect is exaggerated when elevated levels of other greenhouse gases in the atmosphere trap the additional heat.
Most people agree that to curb global warming, a variety of measures need to be taken. On a personal level, driving and flying less, recycling, and conservation reduces a person’s "carbon footprint"—the amount of carbon dioxide a person is responsible for putting into the atmosphere.
On a larger scale, governments are taking measures to limit emissions of carbon dioxide and other greenhouse gases. One way is through the Kyoto Protocol, an agreement between countries that they will cut back on carbon dioxide emissions. Another method is to put taxes on carbon emissions or higher taxes on gasoline, so that people and companies will have greater incentives to conserve energy and pollute less.
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