Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.
This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over the next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.
This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.
Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧） levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.
“We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in the amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicted, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.
【小题1】．According to the new findings, taking steps to prevent northern forest fires may __________.

A．result in a warming climate

B．cause the forest fires to occur more frequently

C．lead to a longer fire season

D．protect the forests and the environment there

【小题2】．The following are all the immediate effects after a forest fire EXCEPT __________.

A．large amounts of greenhouse gases enter the atmosphere

B．the levels of ozone which is a type of oxygen increase

C．snow on the ground mirrors more sunlight back into space

D．ashes from the fire fall on the ice surface and take in more radiation from the sun

【小题3】．Earlier studies about northern forest fires __________.

A．analyze all aspects of how northern fires influence climate

B．indicate that forest fires will pollute the atmosphere

C．suggest that people should take measures to protect environment

D．suggest that the fires will speed up climate warming

【小题4】．The underlined phrase “soak up” in the last paragraph most probably means __________.

A．released

B．absorbed

C．created

D．distributed

【小题5】．From the passage we can draw a conclusion that forest fires in Alaska, Canada and Siberia may ____.

A．warm the climate as the supposition goes

B．allow more snow to reflect more sunlight into space and thus cool the climate

C．destroy large areas of forests and pollute the far-off sea ice

D．help to gain more energy rather than release more energy

Grown-ups know that people and objects are solid. At the movies, we know that if we reach out to touch Tom Cruise, all we will feel is air. But does a baby have this understanding?
To see whether babies know objects are solid. T. Bower designed a method for projecting an optical illusion (视觉影像) of a hanging ball. His plan was to first give babies a real ball, one they could be expected to show surprise in their faces and movements. All the 16 to 24-week-old babies tested were surprised when they reached for the illusion and found that the ball was not there.
Grown-ups also have a sense of object permanence. We know that if we put a box in a room and lock the door, the box will still be there when we come back. But does a baby realize that a ball that rolls under a chair does not disappear and go to never-never land (想像中的地方)?
Experiments done by Bower suggest that babies develop a sense of object permanence when they are about 18 weeks old. In his experiments, Bower used a toy train that went behind a screen. When 16-week-old and 22-week-old babies watched the toy train disappear behind the left side of the screen, they looked to the right, expecting it to re-appear. If the experiment took the train off the table and lifted the screen, all the babies seemed surprised not to see the train. This seems to show that all the babies had a sense of object permanence. But the second part of the experiment showed that this was not really the case. The researcher substituted (替换) a ball for the train when it went behind the screen. The 22-week-old babies seemed surprised and looked back to the left side for the train. But the 16-week-old babies did not seem to notice the switch (更换). Thus, the 16-week-old babies seemed to have a sense of “something permanence,” while the 22-week-old babies had a sense of object permanence related to a particular object.
【小题1】The passage is mainly about ______.

A．babies’ sense of sight

B．effects of experiments on babies

C．babies’ understanding of objects

D．different tests on babies’ feelings

【小题2】. In Paragraph 3, “object permanence” means that when out of sight, “object ______”.

A．still exists

B．keeps its shape

C．still stays solid

D．is beyond reach

【小题3】. What did Bower use in his experiments?

A．A chair & a screen

B．A screen & a train

C．A film & a train

D．A box & a chair

【小题4】 Which of the following statements is true?

A．The babies didn’t have a sense of direction.

B．The older babies preferred toy trains to balls.

C．The younger babies liked looking for missing objects

D．The babies couldn’t tell a ball from its optical illusion.

                              D
The year is 2094. It has been announced that a comet (彗星) is heading towards the Earth . Most of it will miss our planet , but two pieces will probably hit the southern half of the Earth .
On 17 July , a piece four kilometers wide enters the Earth’s atmosphere (大气层) with a massive explosion . About half of the piece is destroyed , but the remaining part hits the South Atlantic at 200 times the speed of sound . The sea boils and a huge hole is made in the sea bed . Huge waves are created and spread outwards from the hole . The wall of water , a kilometer high , rushes towards southern Africa at 800 kilometers an hour . Cities on the African coast are totally destroyed and millions of people re drowned .
Before the waves reach South America , the second piece of the comet lands in Argentina . Earthquakes and volcanoes are set off in the Andes Mountains . The shock waves move north into California and all around the Pacific Ocean . The cities of Los Angeles , San Francisco and Tokyo are completely destroyed by earthquakes . Millions of people in the southern half of the earth are already dead, but the north won’t escape for long . Because of the explosions , the sun is hidden by clouds of dust , temperatures around the world fall to almost zero .Crops are ruined . The sun won’t be seen again for many years . Wars break out as countries fight for food . A year later , no more than 10 million people remain alive .
Could it really happen ? In fact , it has already happened more than once in the history of the Earth . The dinosaurs were on the Earth for over 160 million years . Then 65 million years ago they suddenly disappeared . Many scientists believe that the Earth was hit by a piece of object in space . The dinosaurs couldn’t live through the cold climate that followed and they died out . Will we meet the same end ?
【小题1】What is mainly described in the passage ?

A．A historic discovery .	B．An event of imagination
C．A research on space .	D．A scientific adventure .

【小题2】When the first piece hits the South Atlantic , it causes           .

A．an earthquake	B．damages to cities
C．an Earth explosion	D．huge waves

【小题3】Why can’t the northern half of the earth escape for long ?

A．Because the land is covered with water

B．Because the light and heat from the sun can not reach the earth .

C．Because people there can not live at the temperature of zero .

D．Because wars break out among countries .

Technology: Taking the good without the bad?
Very soon, unimaginably powerful technologies will remake our lives．This could have dangerous consequences, especially because we may not even understand the basic science underlyi ng them．There’s a growing gap between our technological capability and our basic scientific understanding．We can do very clever things with the technology of the future without necessarily understanding some of the science underneath, and that is very dangerous．
The technologies that are particularly dangerous over the next hundred years are nanotechnology （纳米技术）, artificial intelligence and biotechnology．The benefits that they will bring are beyond doubt．But they are going to be very, very dangerous．I’m working in the field of artificial intelligence．I have a model design for something that might be 50,000 million times smarter than the human brain．Target date is 2010．The only thing that's not possible in the film Terminator（终结者） is that the people win．If you're fighting against technology w hich is 50,000 million times smarter than you, you probably will not win．
Nanotechnology．We've all heard of the grey glue problem, that self-replicating nanotech devices might keep on copying until the world has become sticky glue．And certainly in biotechnology, we've really got a big problem because it's converging with nanotechnology and IT．Once you start mixing nanotech with organisms and you start feeding nanotech-enabled bacteria, we can really go an awful lot further than the Borg in Star Trek（星际迷航）．And those superhuman organisms might not like us very much．
Eventually these technologies will become routine．That’s a threat to humanity．I don’t think it’s possible to slow it down．So what we need to do is accelerate the scientific research and try to get some extra tools．The problems facing us in the future are getting bigger and bigger．I think if we don’t get some proper science done, the future is hopeless indeed．
【小题1】From the text, we know that the author’s greatest concern is         ．

A．our lack of technological understanding of the process involved

B．our lack of technological capability

C．creating technology without really understanding the basic science

D．Our refusal to face the consequences of the technology we create

【小题2】It can be inferred from the text that the author         ．

A．thinks people overvalue the capabilities of technology

B．is not optimistic that artificial intelligence will always be used positively

C．thinks that we should take science fiction movies more seriously

D．believes artificial intelligence is the greatest threat we face technologically

【小题3】Why does the author say it is not possible in the film Terminator that the humans win?

A．Because the power of the technology is exaggerated（夸大）．

B．Because the strength of the machines is much greater．

C．Because machines with that much intelligence can easily defeat humans．

D．Because human beings are not courageous enough to win the battle．

Can you remember a morning when you’ve woken up to the ring of your alarm clock and wished you could stay in bed? You haven’t slept well, your hair is a mess. Worse, you can’t stop yawning. Yawning is universal to humans and many animals. Cats, dogs and fish yawn just like humans do! Yawning is an involuntary(无意识的,不自觉的) action during which you open your mouth and breathe deeply. The average duration of a yawn is about 6 seconds.
The purpose and cause of yawning are still a mystery. Scientists are not sure what causes a yawn. People yawn when they are tired or bored, but they also yawn when they aren’t. There are many ideas explaining why we yawn.
One idea is that yawning is a way for the body to become more alert by taking in more oxygen. A yawn increases the heart rate, forces carbon dioxide out of the lungs and blood stream, and brings oxygen to the brain. But one study showed that volunteers given a lot of oxygen did not yawn any less than before, while those given a lot of carbon dioxide did not yawn more.
Another idea is that early humans used yawning as a form of communication. If one decided it was time to sleep, they would tell the others by yawning and they would do it in return to show they agreed.
A third explanation comes from psychology professor Gordon Gallup of University at Albany in New York. He said that as people yawn, they cool off their brains. “Brains are like computers.” he said. “They only operate efficiently and effectively when they’re cool. Many things connected to yawning, like being tired, make the brain hot, and yawning can reduce the heat.”
Scientists have sent people into space, and created terrible nuclear weapons, but there are lots of seemingly simple things, such as why we yawn, or hiccup（打嗝）, that they can’t figure out. Next time you are in class in the morning, let out a big yawn and watch to see how many of your classmates yawn in response!
【小题1】What’s the purpose of the description of how bad you may feel when you’re woken up in the morning?

A．To explain why humans yawn.

B．To explain how humans start yawning.

C．To lead into the topic of yawning.

D．To complain about being woken up by the clock.

【小题2】Which is not among the possible reasons for yawning mentioned in the passage?

A．A way to show that you feel hot.

B．A way to get rid of carbon dioxide.

C．A way to cool off your brain.

D．A way to communicate.

【小题3】In which situation are you likely to yawn?

A．When you feel frustrated.

B．The weather is hot.

C．Someone else yawns near you.

D．When you breathe in a lot of carbon dioxide.

【小题4】What can we learn from the passage?

A．The real reason why humans and most animals yawn.

B．Hiccups are an involuntary human action similar to yawns.

C．The more an action can be studied, the easier it is to research.

D．Finding out why humans yawn should be easier than sending people into space.

Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.
Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines(刺) that discourage grass-eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.
Some plants , such as the oak trees, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal’s teeth.
Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar(毛虫)bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.
Many plants depends on both physical and chemical defenses. A certain plant in China , for instance, has prickly(多刺的) leaves, and each prickle contains poisonous venom(毒液). A single experience with this kind of plant will teach an animal to stay away from it in the future.
【小题1】The holly plant has more spines on the lower leaves because most animals        .

A．can get the lower leaves easily	B．like eating the lower leaves
C．like leaves with sharp spines	D．have teeth and claws

【小题2】To defend themselves , oak trees use           .

A．chemical means	B．physical means
C．bitter chemicals	D．sandy materials

【小题3】 How does tobacco protect itself against an attack from a caterpillar?

A．Its leaves fight against the attack by physical means.

B．Its roots send a messenger to discourage the caterpillar.

C．Its roots increase the production of nicotine when it is attacked.

D．Its leaves produce poisonous sand to drive the caterpillar away.

【小题4】What would be the best title for this passage?

A．Plants and Animals	B．How Plants Defend Themselves
C．Attacks and Defenses	D．How Animals Eat Plant Leaves

About twenty of us had been fortunate enough to receive invitations to a film-studio(影棚)to take part in a crowd-scene. Although our "act" would last only for a short time, we could see quite a number of interesting things.
We all stood at the far end of the studio as workmen prepared the scene, setting up trees at the edge of a winding path. Very soon, bright lights were turned on and the big movie-camera was wheeled into position. The director shouted something to the camera operator and then went to speak to the two famous actors nearby. Since it was hot in the studio, it came as a surprise to us to see one of the actors put on a heavy overcoat and start walking along the path. A big fan began blowing tiny white feathers down on him, and soon the trees were covered in "snow". Two more fans were turned on, and a "strong wind" blew through the trees. The picture looked so real that it made us feel cold.
The next scene was a complete contrast (对比). The way it was filmed was quite unusual. Pictures in front taken on an island in the Pacific were shown on a glass screen (幕). An actor and actress stood of the scene so that they looked as if they were at the water’s edge on an island. By a simple trick like this, palm trees, sandy beaches, and blue, clear skies had been brought into the studio!
Since it was our turn next, we were left wondering what scene would be prepared for us. For a full three minutes in our lives we would be experiencing the excitement of being film "stars"!
【小题1】Who is the author?

A．A cameraman.

B．A film director.

C．A crowd-scene actor.

D．A workman for scene setting.

【小题2】 What made the author feel cold?

A．The heavy snowfall.	B．The man-made scene.
C．The low temperature.	D．The film being shown.

【小题3】What would happen in the "three minutes" mentioned in the last paragraph?

A．A new scene would be filmed.

B．More stars would act in the film.

C．The author would leave the studio.

D．The next scene would be prepared.

Why should mankind explore space? Why should money, time and effort be spent exploring and researching something with so few apparent benefits? Why should resources be spent on space rather than on conditions and people on Earth? These are questions that, understandably, are very often asked．
Perhaps the best answer lies in our genetic makeup（基因构成） as human beings．What drove our ancestors to move from the trees into the plains, and on into all possible areas and environments? The wider the spread of' a species, the better its chance of' survival． Perhaps the best reason for exploring space is this genetic tendency to expand wherever possible． Nearly every successful civilization has explored, because by doing so, any dangers in surrounding areas can be identified and prepared for． Without knowledge, we may be completely destroyed by the danger． With knowledge, we can lessen its effects．
Exploration also allows minerals and other potential（潜在的） resources to be found．Even if' we have no immediate need of them, they will perhaps be useful later． Resources may be more than physical possessions． Knowledge or techniques have been acquired through exploration．The techniques may have medical applications which can improve the length or quality of our lives．We have already benefited from other spin-offs including improvements in earthquake prediction, in satellites for weather forecasting and in communications systems． Even non-stick pans and mirrored sunglasses are by-products （副产品） of technological developments in the space．
While many resources are spent on what seems a small return, the exploration of' space us．While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers． The danger exists, but knowledge can help human being to survive． Without the ability to reach out across space, the chance to save ourselves might not exist．
While Earth is the only planet known to support life, surely the adaptive ability of humans would allow us to live on other planets． It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future．
【小题1】Why does the author mention the questions in Paragraphl ?

A．To express his doubts．

B．To introduce points for discussion．

C．To compare different ideas．

D．To describe the conditions on Earth．

【小题2】What is the reason for exploring space based on Paragraph2 ?

A．Humans are nature-born to do so．

B．Humans have the tendency to fight．

C．Humans may find new sources of food．

D．Humans don't like to stay in the same place．

【小题3】The underlined word “spin-offs” in Paragraph 3 probably refers to       ．

A．survival chances	B．potential resources
C．unexpected benefits	D．physical possessions

【小题4】What makes it possible for humans to live on other planets'?

A．Our genetic makeup．	B．The adaptive ability of' humans．
C．Resources on the earth．	D．By-products in space exploration．

【小题5】Which of the following statements can best sum up the passage'?

A．Space exploration has created many wonders．

B．Space exploration provided the best value for money．

C．Space exploration can benefit science and technology．

D．Space exploration may help us avoid potential problems on Earth．

About twenty of us had been fortunate enough to receive invitations to a film-studio(影棚)to take part in a crowd-scene. Although our “act" would last only for a short time, we could see quite a number of interesting things.
We all stood at the far end of the studio as workmen prepared the scene, setting up trees at the edge of a winding path. Very soon, bright lights were turned on and the big movie-camera was wheeled into position. The director shouted something to the camera operator and then went to speak to the two famous actors nearby. Since it was hot in the studio, it came as a surprise to us to see one of the actors put on a heavy overcoat and start walking along the path. A big fan began blowing tiny white feathers down on him, and soon the trees were covered in “snow". Two more fans were turned on, and a "strong wind" blew through the trees. The picture looked so real that it made us feel cold.
The next scene was a complete contrast (对比). The way it was filmed was quite unusual. Pictures in front taken on an island in the Pacific were shown on a glass screen (幕). An actor and actress stood of the scene so that they looked as if they were at the water’s edge on an island. By a simple trick like this, palm trees(棕榈树), sandy beaches, and blue, clear skies had been brought into the studio!
Since it was our turn next, we were left wondering what scene would be prepared for us. For a full three minutes in our lives we would be experiencing the excitement of being film "stars"!
【小题1】Who is the author?

A．A cameraman.

B．A film director.

C．A crowd-scene actor.

D．A workman for scene setting.

【小题2】What made the author feel cold?

A．The heavy snowfall.

B．The man-made scene.

C．The low temperature.

D．The film being shown.

【小题3】 What would happen in the "three minutes" mentioned in the last paragraph?

A．A new scene would be filmed.

B．More stars would act in the film.

C．The author would leave the studio.

D．The next scene would be prepared.

Honey(蜂蜜)from the African forest is not only a kind of natural sugar, it is also delicious. Most people, and many animals, like eating it. However, the only way for them to get that honey is to find a wild bees' nest(巢)and take the honey from it. Often, these nests are high up in trees, and it is difficult to find them. In parts of Africa, though, people and animals looking for honey have a strange and unexpected helper一a little bird called a honey guide.
The honey guide does not actually like honey, but it does like the wax (蜂蜡) in the beehives (蜂房). The little bird cannot reach this wax, which is deep inside the bees’ nest. So, when it finds a suitable nest, it looks for someone to help it. The honey guide gives a loud cry that attracts the attention of both passing animals and people. Once it has their attention, it flies through the forest, waiting from time to time for the curious animal or people as it leads them to the nest. When they
finally arrive at the nest, the follower reaches in to get at the delicious honey as the bird patiently waits and watches. Some of the honey, and the wax, always falls to the ground, and this is when the honey guide takes its share.
Scientists do not know why the honey guide likes eating the wax, but it is very determined in its efforts to get it. The birds seem to be able to smell wax from a long distance away. They will quickly arrive whenever a beekeeper is taking honey from his beehives, and will even enter churches when beeswax candles are being lit.
【小题1】Why is it difficult to find a wild bees' nest?

A．It's small in size.	B．It's hidden in trees.
C．It's covered with wax.	D．It's hard to recognize.

【小题2】 What do the words "the follower" in Paragraph 2 refer to?

A．A bee.	B．A bird.
C．A honey seeker.	D．A beekeeper.

【小题3】The honey guide is special in the way________.

A．it gets its food	B．it goes to church
C．it sings in the forest	D．it reaches into bees' nests

【小题4】What can be the best title for the text?

A．Wild Bees	B．Beekeeping in Africa
C．Wax and Honey	D．Honey-Lover's Helper