All too often, a choice that seems sustainable(可持续的)turns out on closer examinat

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All too often, a choice that seems sustainable(可持续的)turns out on closer examination to be problematic. Probably the best example is the rush to produce ethanol(乙醇) for fuel from corn. Corn is a renewable resource —you can harvest it and grow more, almost limitlessly. So replacing gas with corn ethanol seems like a great idea.
One might get a bit more energy out of the ethanol than that used to make it, which could still make ethanol more sustainable than gas generally, but that’s not the end of the problem. Using corn to make ethanol means less corn is left to feed animals and people, which drives up the cost of food. That result leads to turning the fallow land –including, in some cases, rain forest in places such as Brazil—into farmland, which in turn gives off lots of carbon dioxide (CO) into the air. Finally, over many years, the energy benefit from burning ethanol would make up for the forest loss. But by then, climate change would have progressed so far that it might not help.
You cannot really declare any practice “sustainable” until you have done a complete life-cycle analysis of its environmental(环境的) costs. Even then, technology and public keep developing, and that development can lead to unforeseen and undesired results. The admirable goal of living sustainably requires plenty of thought on an ongoing basis.
小题1:What might directly cause the loss of the forest according to the text?

A．The growing demand for energy to make ethanol

B．The increasing carbon dioxide in the air

C．The greater need for farmland

D．The big change in weather.

小题2:The underlined word “it” in the second paragraph refers to “ ”

A．the energy benefit	B．the forest loss
C．climate change	D．burning ethanol

小题3:The author thinks that replacing gas with corn ethanol is .

A．impractical

B．acceptable

C．admirable

D．useless

小题4:What does the author mainly discuss in the text?

A．Technology	B．Sustainability
C．Ethanol energy	D．Environmental protection

答案

小题1:C
小题2:A
小题3:A
小题4:B

解析

试题分析：作者主要谈论的是可持续性发展的判断依据以及用相关一些事实来进行佐证其论点。
小题1:C推理判断题。注意问的是直接原因。That result leads to turning the fallow land — including, in some
cases, rain forest in places such as Brazil — into farmland(这个结果会导致一些休闲地<在一些情况下，包括位于巴西等地的热带雨林>被转化为农场)。
小题2:A词义猜测题。根据上下文可知是指能源优势。
小题3:A推理判断题。根据全文可知作者认为用corn代替gas是不符合实际的，会带来很多意想不到的问题。
小题4:B主旨大意题。读完全文我们可以知道，作者主要谈论的是可持续性发展的判断依据以及用相关一些事实来进行佐证其论点。该题容易误选D。

举一反三

One reaction to all the concern about tropical deforestation（毁林） is a blank stare that asks the question, "Since I don"t live there, what does it have to do with me?"
The answer is that your way of life, wherever you live in the world, is tied to the tropics in many ways. If you live in a house, wash your hair, eat fruits and vegetables, drink soda, or drive a car, you can be certain that you are affected by the loss of tropical forests.
Biologically, we are losing the richest regions on earth when, each minute, a piece of tropical forest, the size of ten city blocks, disappears. As many as five million species of plants, animals, and insects (40 to 50 percent of all living things) live there, and are being lost faster than they can be found and described. Their loss is immeasurable.
Take rubber for example. For many uses, only natural rubber from trees will do. Synthetics are not good enough. Today over half the world"s commercial rubber is produced in Malaysia and Indonesia, while the Amazon"s rubber industry produces much of the world"s four million tons. And rubber is an important material in making gloves, balloons, footwear and many sporting goods. Thousands of other tropical plants are valuable for their industrial use.
Many scientists strongly believe that deforestation contributes to the greenhouse effect -- or heating of the earth from increased carbon dioxide in the atmosphere. As we destroy forests, we lose their ability to change carbon dioxide into oxygen.
Carbon dioxide levels could double within the next half-century, warming the earth by as much as 4.5 degrees. The result? A partial melt-down of polar ice caps, raising sea levels as much as 24 feet; even 15 feet could threaten anyone living within 35 miles of the coast. Unbelievable? Maybe. But scientists warn that by the time we realise the severe effects of tropical deforestation, it will be 20 years too late.
Can tropical deforestation affect our everyday lives? Now, you should have got the answer.
小题1:The underlined word "synthetics" probably means_________.

A．natural rubber	B．tropical materials
C．man-made material	D．commercial rubber

小题2:According to the passage, which of the following is NOT true?

A．The forests are losing their function in turning carbon dioxide into oxygen.

B．Many of our daily uses are related to the tropical forests.

C．Tropical plants can be used to make industrial products.

D．High carbon dioxide levels will make the earth warmer.

小题3:The author"s attitude towards the tropical deforestation is _________ .

A．puzzling

B．cold

C．supporting

D．opposed

小题4:Which of the following might be the best title for the passage?

A．Tropical Forests	B．The Value of Tropical Forests
C．Tropical Forests and Our Life	D．The Greenhouse Effects

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Have you ever wondered why birds sing? Maybe you thought that they were just happy．After all, you probably sing when you are happy．
Some scientists believe that birds do sing some of the time just because they are happy．However they sing most of the time for a very different reason．Their singing is actually a warning to other birds to stay out of their territory．
Do you know what a “territory” is? A territory is an area that an animal, usually the male, claims (声称) as its own．Only he and his family are welcome there． No other families of the same species are welcome．Your house is your territory where only your family and friends are welcome．If a stranger should enter your territory and threaten you, you might shout．Probably this would be enough to frighten him away．
If so, you have actually frightened the stranger away without having to fight him．A bird does the same thing．But he expects an outsider almost any time, especially at nesting (筑巢) season．So he is screaming all the time, whether he can see an outsider or not．This screaming is what we call a bird’s song, and it is usually enough to keep an outsider away．
小题1:Some scientists believe that most of the time bird’s singing is actually ______．

A．an expression of happiness	B．a way of warning
C．an expression of anger	D．a way of greeting

小题2:What is a bird’s “territory”?

A．A place where families of other species are not accepted.

B．A place where a bird may shout at the top of its voice．

C．An area for which birds fight against each other．

D．An area which a bird considers to be its own．

小题3:Why do birds keep on singing at nesting season?

A．Because they want to invite more friends．

B．Because their singing helps frighten outsiders away．

C．Because they want to find outsiders around．

D．Because their singing helps get rid of their fears．

小题4:How does the writer explain birds’ singing?

A．By comparing birds with human beings．

B．By reporting experiment results．

C．By describing birds’ daily life．

D．By telling a bird’s story．

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Another thing an astronaut has to learn about is eating in space．Food is weightless, just as men are．
Food for space has to be packed in special ways．Some of it goes into tubes that a man can squeeze into his mouth．Bite-sized cookies are packed in plastic．
There is a good reason for covering each bite．The plastic keeps pieces of food from traveling in the spaceship．On the earth very small pieces of food would simply fall to the floor．But gravity doesn’t pull them to the floor when they are out of the plastic in a spaceship．They move here and there and can get into a man’s eyes or into the spaceship’s instruments． If any of the instruments is blocked, the astronauts may have trouble getting safely home．
As astronauts travel on longer space trips, they must take time to sleep． An astronaut can fit himself to his seat with a kind of seat belt. Or, if he wants to, he can sleep in a sleeping bag which is fixed in place under his seat．But be careful he must put his hands under the belt when he goes to sleep．This is because he is really afraid that he might touch one of controls that isn’t supposed to be touched until later．
小题1:Why would astronauts cover each bite of food in space？____

A．Because small pieces of food would fall down to the floor．

B．Because weightless pieces of food might make trouble when they travel around．

C．Because they haven’t enough food for longer trips．

D．Because astronauts don’t want to waste food．

小题2:In a spaceship, astronauts can ____．

A．walk just as they do on the earth．

B．not eat anything because it’s dangerous．

C．control the spaceship when they are sleeping．

D．not litter small things or it will make trouble．

小题3:Why does an astronaut put his hand under his belt when he sleeps？____

A．Because he thinks it is comfortable to sleep in that way in space．

B．Because he doesn’t want to touch any controls when he sleeps．

C．Because the instruments of the spaceship are easily broken．

D．Because he is afraid that the seat will move．

小题4:The best title of this article is ____．

A．Eating and Sleeping in Space

B．How Astronauts Eat in Space

C．Food for Space

D．How Astronauts Sleep in Space

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Did you know that the position you choose to sleep in says something about what kind of person you are?
A study of 1,000British people has been done by Chris,a British professor and director of the Sleep Assessment and Advisory Service in the UK.It looked at the six most common sleeping positions and which personalities tend to match them.Have a look.
1. Fetus (胎儿) position – This is the most common sleeping position. About 41 percent of the participants said they sleep in this position. These sleepers may appear to be strong but they are usually sensitive (敏感的) and shy. The more they curl (蜷缩) up, the more worried they are.
2. Log position (树干睡姿) – This is the second most common position. People who sleep like a log are usually stubborn.
3. Yearner position (向往型睡姿) – This position says that you are open-minded and eager (急切的) to face challenges.
4. Soldier position – These sleepers lie on their backs with their arms down and close to the body. They are usually reserved and quiet.
5. Freefall position – People who sleep in this position are outgoing (外向的) but feel a lack of control in their lives. This is the least comfortable position.
6. Starfish position – People who sleep like this are good listeners, helpful, and uncomfortable being the center of attention.
小题1:What is the main idea of this passage?

A．Sleeping position decides personality.

B．Sleeping position reflects personality.

C．What the six different sleeping positions are like.

D．Different people have different sleeping positions.

小题2:Which of the following pictures shows “soldier position”?

A．

B．

C．

D．

小题3:According to the passage, which of the following statements is correct?

A．Those sleeping in fetus position are always strong.

B．Those sleeping in log position changes their ideas easily.

C．Those sleeping in freefall position usually feel uncomfortable in their lives.

D．Those sleeping in starfish position may feel uneasy when focused on.

小题4:What does the underlined word “participants” in paragraph 3 most probably mean?

A．Fetus

B．British people

C．People surveyed

D．Sleepers

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What makes a person a scientist？Does he have ways or tools of learning that are different from those of others？The answer is “no”. It isn’t the tools a scientist uses but how he uses these tools which make him a scientist. You will probably agree that knowing how to use a power is important to a carpenter(木匠).You will probably agree，too，that knowing how to investigate(调查)，how to discover information，is important to everyone. The scientist，however，goes one step further；he must be sure that he has a reasonable answer to his questions and that his answer he gets to many questions is into a large set of ideas about how the world works.
The scientist’s knowledge must be exact. There’s no room for half right or right just half the time. He must be as nearly right as the conditions permit. What works under one set of conditions at one time must work under the same conditions at other times. If the conditions are different，any changes the scientist observes in a demonstration(实证)must be explained by the changes in the conditions. This is one reason why investigations are important in science. Albert Einstein，who developed the Theory of Relativity，arrived at this theory through mathematics. The accuracy(正确性)of his mathematics was later tested through investigation. Einstein’s ideas were proved to be correct. A scientist uses many tools for measurements. Then the measurements are used to make mathematical calculations(计算)that may test his investigations.
小题1:What makes a scientist according to the passage？

A．The tools he uses.	B．His ways of learning.
C．The way he uses his tools.	D．The various tools he uses.

小题2:“...knowing how to investigate，how to discover information，is important to everyone.” The writer says this to show_______.

A．the importance of information

B．the difference between scientists and ordinary people

C．the importance of thinking

D．the difference between carpenters and ordinary people

小题3: A sound（合理的） scientific theory should be one that_______.

A．works under one set of conditions at one time and also works under the same conditions at other times

B．doesn’t allow any change even under different conditions

C．leave no room for improvement.

D．can be used for many purposes

小题4:What is the main idea of the passage？

A．Scientists are different from ordinary people.

B．The Theory of Relativity.

C．Exactness is the core(核心)of science.

D．Exactness and way of using tools are the keys to making of a scientist.

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