The earth is the only planet that scientists are certain has life .What does the earth have that the other planets don’t ? For one thing , the earth has just the right temperature . As the third planet from the sun , the earth seems to be just the right distance away . The planets that are closer to the sun are so hot that their surfaces bake in the sun . The farthest planets are cold balls .
When the earth developed— which scientists believe may have happened about billions of years ago , many gases covered the earth . The gases caused the earth to be hot . But something wonderful happened . The temperature was just right for thick clouds to form . It rained very hard for a very long time . This gave the earth its oceans . Water made it possible for plants to grow . The plants created oxygen in the atmosphere . Oxygen is the gas that humans and animals breathe .
Only one other planet in the solar system seems to be something like the earth . That planet is Mars . Mars is smaller than the earth , and it is quite a bit cooler . But it is not too cold for humans . On some days , the temperatures are as cold as a winter day in the northern United States . If you wore a special spacesuit , you could walk around on Mars . You would have to bring your own air to breathe , though . The air on Mars is too thin to breathe . Mars has the largest volcano in the solar system . It is sixteen miles high . The highest volcano on the earth is five miles high . The most unexpected sight on Mars is dried-up river beds . Scientists believe that Mars was once much wetter that it is now . Does this mean there could have been living things on Mars ? Scientists are not sure , but there has been no sign so far .
【小题1】It is the       on the earth that makes life possible .

A．temperature

B．water

C．oxygen

D．temperature , water and oxygen

【小题2】The underlined phrase “ the third planet ” means       .

A．the sun

B．the earth

C．the moon

D．Mars

【小题3】Which planet in the solar system is most like the earth ?

A．Mars .

B．Moon .

C．Sun .

D．Mars and Moon .

【小题4】Which of the following is TRUE ?

A．The earth has a history of about 4 million years .

B．There is no air on Mars .

C．The largest volcano on Mars is over three times higher than the highest one on the earth

D．Scientists believe there are living things on Mars .

【小题5】The best title for the passage should be        .

A．Living Things on Our Earth	B．The Moon
C．Living Things on the Moon	D．Mars Is Most Like the Earth

Some years ago, a Miami woman walking through an office building noticed two men standing together．Several minutes after her leaving, the men murdered a person working in the building．The police determined that the woman was the only witness and could possibly describe them．However, her memory of the men proved disappointingly unclear．Several days later, psychologist Ronald Fisher was brought in to obtain a more complete account from the woman．His interview produced a breakthrough—the woman reported a clear picture of one of the suspects．The important information enabled the police to arrest the suspect and close the case．
The police asked Fisher for help because of his rich knowledge in cognitive(认知) interview, a kind of memory - rebuilding process．Memory researchers have found that people trying to remember a past event often only recall part of the relevant information．Human memory is selective and it is often distorted by stress．But a person's accurate recall of an event or understanding of a question can be improved using specific interviewing techniques．The "cognitive interview" was developed in the late 1990s．It encourages the witness to take an active role in recalling information rather than giving answers only to someone else's questions．The witness first describes what happened in his or her own words, with no interviewer interruptions．The interviewer then goes further with specific techniques, such as having the witness tell the details of what happened from different perspectives （角度） ．
The cognitive interview focuses on guiding witnesses through four general recalling techniques: thinking about physical surroundings and personal feelings that existed at the time of past events; reporting everything that connects to mind about those events, no matter how broken it is retelling events in a variety of time orders, such as from beginning to end, end to beginning, forward or backward; and adopting different perspectives while recalling events．
Experiments with police detectives trained in this demanding interview method find that they obtain nearly 50% more information from witnesses than before training, while error rates remain about the same．It is proved that cognitive interviews are quite important tools in improving the accuracy and completeness of witness testimony （证词）．
【小题1】The purpose of the passage is to _____．

A．give an account of a murder case.

B．introduce an idea of cognitive interview.

C．prove Fisher was an expert in cognitive interview.

D．help a witness to recall information in a cognitive interview.

【小题2】What is required to recall in a cognitive interview for a witness?

A．The exact time at which a murder took place．

B．The information about the event in the time order．

C．The important things that come to his or her mind．

D．The surroundings and feelings at the time of the event．

【小题3】The key point in a cognitive interview is that     .

A．the witness is encouraged to take part in recalling information.

B．the interviewer should interrupt the witness from time to time.

C．the interview should take place outside the police station.

D．the witness should recall details at the scene of the event.

【小题4】The underlined word "distorted" in the passage probably means " ____

A．arranged

B．balanced

C．changed

D．examined

When building houses, people used to think about not only the climate of the areas but also the building materials and the fashions for their houses. However, since electricity became more and more expensive, people began to pay much more attention to the energy they could get for their houses and the new ways they could find to protect their houses from both cold and heat.
Now, houses of an old yet new type have been widely built. In some parts of the world, people share their houses with their livestock. During cold weather, they gather their cows, goats, or other animals and keep them on the first floor of their houses. The reasons are that the animals can be protected from the cold and that they can help to heat the houses as well. The body heat given off by the animals rises to the second floor of the houses, where people live. By sharing their houses with their livestock, people gain a source of heat.
People who live in or near cities do not usually keep livestock. However, home builders use the fact that heat rises. This natural law can be used in building houses in these areas. Instead of keeping livestock on the first floor, builders fill it with large rocks. As they are open to the sun’s rays during cold weather, these rocks take in heat. They also give off the heat, and, of course, the warm air rises into the living areas of the houses. So these houses are energy-saving.
House building becomes a great challenge to building designers and energy engineers. They try to meet this challenge by learning from old traditions and by using modern technology. And someday in the future, people will be able to live in more energy-saving houses.
【小题1】What did people begin to consider as electricity was no longer cheap?

A．The climate of their areas

B．The building materials for their houses

C．The fashions for their houses

D．The energy for their houses

【小题2】People in some areas gain a source of heat by _________.

A．keeping their livestock downstairs

B．protecting their livestock from the cold

C．sharing their houses only with their cows

D．living on the second floor with their livestock

【小题3】The underlined words “natural law” in the third paragraph refer to the fact that ________.

A．heat raises the temperature in the houses

B．heat goes in the upward direction

C．heat goes up if temperature is raised

D．heat increases the temperature of rocks

【小题4】From the passage, we can conclude that _______ .

A．people will no longer consider building materials in the future

B．almost all people will move into the houses heated by large rocks

C．energy-saving buildings will become more popular in the future

D．energy engineers will devote themselves only to modern technology

【小题5】What is the main idea of the passage?

A．Energy-saving house building

B．House building is a great challenge

C．How to live in energy-saving houses

D．Energy-saving houses’ bright future

Since people first sent rockets into space in the 1950s, we have been leaving behind all sorts of things. Some of them, like the camera, were lost by astronauts while they did work outside their spaceship. But much of the space junk is made up of little pieces of things that were once bigger objects, until they struck each other and broke apart.
Some things we send into space fall back toward the earth and burn up in the atmosphere. But larger pieces sometimes survive the extreme heat and hit the ground or the ocean at great speeds. So there is always concern that something may fall from the sky and do some harm.
But space junk falling on housetops (屋顶) is not the biggest worry. Scientists are concerned about what happens when an empty rocket strikes another while orbiting (绕轨道飞行) the earth. Two big things become many smaller things. They then hit other things. The pieces get smaller and smaller until they form a cloud of junk that blocks the path of future space vehicles.
So what can be done to clean up the space around our planet? Marco Castronuovo, an Italian researcher, talks about sending a satellite into space that would get very close to some of the larger pieces of space junk. The satellite would connect a small rocket to the useless object. When the rocket explodes, it pushes the junk into a lower and slower orbit, nearer the earth. After a time, the junk burns up in the atmosphere.
Mr. Castronuovo has proposed (提议) using a number of small satellites with robotic arms. One arm would catch the space junk, and another arm would connect the rocket. He imagines that each satellite would jump from one large piece of junk to another. He thinks this method could destroy about ten large objects each year.
Scientists have been concerned about space junk for many years. Right now, the costs of the clean-up have been too great. Mr. Castronuovo says his system could be put in place for a much more reasonable amount of money.
【小题1】Much of the space junk _____.

A．was thrown by the astronauts

B．is from broken spaceship

C．is made up of small pieces of things

D．returns to the earth piece by piece

【小题2】Scientists are most worried that the space junk _____.

A．will stop the future space vehicles

B．will do harm to the atmosphere

C．will fall on the housetops

D．will burn up in space

【小题3】What does Marco Castronuovo think of his system?

A．It can remove space junk completely.

B．It can save a large amount of money.

C．It can create a large amount of space.

D．It can develop robotic technology.

It’s a sure sign that summer is over and winter is on the way — leaves that were once deep green turn red, yellow and bright orange. It happens every autumn. But did you ever wonder why?
The leaves start changing color when the nights start getting longer and the temperature starts getting cooler. Some scientists think that as the number of daylight hours shrinks, the leaves stop making chlorophyll which makes plants green. The reason is that the process of making chlorophyll requires sunlight. But according to horticulture (园艺) educator Susan Rose from Colorado State University, it turns out leaves don’t really change color at all. “The fall colors are actually there all along,” she said. “But they are covered by the green chlorophyll. As the chlorophyll stops being produced, the other colors can shine through.”
The kind of color that the leaves are going to change to is determined by the plant’s genetic (基因的) background. In some places, the leaves start changing color in September — before autumn even officially begins. In other places, they don’t change until late October or even November. Some scientists say the leaves have been changing color later than usual in recent years. And they think global warming has something to do with that.
In one study, researchers found that the growing season in the Northern Hemisphere was nearly a week longer, on average, in 2008 than it was in 1982. And a professor from Harvard University found that the leaves, west of Boston, Massachusetts, are changing color about three days later than they used to. However, other scientists disagree with the global warming theory. Susan Rose said the leaves in her part of Colorado are changing “right on schedule.” But the leaves in other parts of that state are running a little late. “The lateness in the mountains may have something to do with the really warm late summer and early fall,” she said. “But I’m afraid that’s just a guess.”
【小题1】According to Susan Rose, _____.

A．the fall colors are always in leaves

B．leaves make chlorophyll all the seasons

C．leaves’ changing color have nothing to with the weather

D．leaves begin changing color because they start making chlorophyll

【小题2】The underlined word “shrinks” in Paragraph 2 could best be replaced by _____.

A．reduces

B．increases

C．lasts

D．appears

【小题3】Scientists guess leaves change color later than usual probably as a result of _____.

A．genetic background	B．dry weather
C．global warming	D．low temperature

【小题4】The purpose of the last paragraph is to tell readers _____.

A．why leaves change color at fall

B．leaves change color at different time

C．the effects of the global warming on plants

D．different opinions on the lateness of leaves’ changing color

Many animals recognize their food because they see it. So do humans. When you see an apple or a piece of chocolate, you know that these are things you can eat. You can also use other senses when you choose your food. You may like it because it smells good or because it tastes good. You may dislike some types of food because they do not look, smell or taste very nice. Different animals use different senses to find and choose their food. A few animals depend on only one of their senses, while most animals use more than one sense.
Although there are many different types of food, some animals spend their lives eating only one type. The giant panda eats only one particular type of bamboo(竹子) . Other animals eat only one type of food even when given the choice. A kind of white butterfly(蝴蝶) will stay on the leaves of a cabbage, even though there are plenty of other vegetables in the garden. However, most animals have a more varied(多样化) diet . The bear eats fruits and fish. The fox eats small animals, birds and fruits. The diet of these animals will be different depending on the season.
Humans have a very varied diet. We often eat food because we like it and not because it is good for us. In countries such as France and Britain, people eat foods with too much sugar. This makes them overweight, which is bad for their health. Eating too much red meat and animal products, such as butter, can also be bad for the health. Choosing the right food, therefore, has become an area of study in modern life.
【小题1】We can infer from the text that humans and animals _________.

A．depend on one sense in choosing food

B．are not satisfied with their food

C．choose food in similar ways

D．eat entirely different food

【小题2】Which of the following eats only one type of food?

A．The white butterfly.	B．The small bird.
C．The bear.	D．The fox.

【小题3】Certain animals change their choice of food when ___________.

A．the season changes

B．the food color changes

C．they move to different places

D．they are attracted by different smells

A sandstorm, also known as a dust storm, is exactly what it sounds like. A very strong windstorm especially in the desert carries clouds of sand or dust that greatly reduces visibility. This wind is usually caused by convection currents (对流气流), which are created by intense heating of the ground, and is usually strong enough to move entire sand dunes. Air is unstable when heated, and this instability in the air will cause higher winds to mix with winds in the lower atmosphere, producing strong surface winds.
Sandstorms can disturb people’s travel, and can sometimes destroy whole roads, and dry flat areas. Similar dust storms can be found on the planet Mars, and are thought to be seasonal. Today, the destruction of forests and too much farming of farmland can lead to sandstorms. Too much use of water resources can also cause sandstorms.
In the United States of America, sandstorms are rare because of the lack of large deserts and more importantly the development of proper agricultural techniques. The last recorded destructive sandstorm in American history was the Dust Bowl, which occurred on July 16, 1971 and was widely recorded by meteorologists (气象学家).
To protect themselves from sandstorms, some people wear protective suits. Special equipment can be fixed in some cars to prevent sand from getting into the engine. Sandstorms can cause coughs, and the sand and dust has also been known to carry “infectious diseases”. Sand particles, unlike dust ones, will block air passages, and cause a person who breathes them in to choke. Dust particles may cause an allergic (过敏的) reaction.
【小题1】Which of the following plays the first part in forming sandstorms?

A．The instability of the sand.

B．The instability of the wind.

C．The intense heating of the ground.

D．The speed of the wind.

【小题2】From the second paragraph, we can learn that at present _______.

A．sandstorms are more often seen on Mars than on Earth

B．sandstorms have led to the lack of clean water resources

C．farming brings more harm than benefits to humans

D．human activities are a major cause of sandstorms

【小题3】The author will most probably agree that ________.

A．there will soon be no sandstorms in the USA

B．humans haven’t thought of any way to deal with sandstorms

C．death caused by sandstorms is increasing all the time

D．humans should make more efforts to stop soil turning into desert

Last spring, members of Alaska’s Troop 34, based in Fairbanks, trudged (跋涉) out into the snowy wilderness to take part in their state’s Take a Kid Trapping program. In many parts of the state, beavers （海狸）are pests and need to be controlled.
The 10－to－12－year－old girls found out where beavers lived, set traps, and skinned the two animals they caught. The girls hope to catch ten more beavers so that the entire troop can make mittens and hats with the fur. They also want to cook beaver meat.
Troop leaders and members say the Scouts are doing a good deed by helping control the state’s beaver population. But animal－rights activists say trapping is cruel. They want the Girl Scouts to stop in their tracks.
Beavers aren’t only causing a problem in Alaska. Residents in Sampson County, N.C., have turned to a local committee to help them battle the growing beaver population there.
County landowners are frustrated after the county spent more than $ 50,000 in eight years trying to reduce the beaver population through a government program. The joint state and federal program included paying money to trappers for every beaver carcass they trapped.
Many local residents say that the program didn’t work because there were too few trappers. That’s why the county set up its own committee to investigate other ways to control the area’s beaver population.
The county will rely on its own beaver－trapping program. It has hired a trapper to set traps in various areas. The county will pay $10 for every beaver carcass.
Why do many people say that beavers are a nuisance? For beavers to survive, they need lots of water. Water provides the large rodent （啮齿动物）with a place to hide from meat – eating animals. Beavers also store food underwater for the winter. When there’s not enough water in a particular area, beavers get busy building dams.
Beaver dams can cause major flooding and damage to the surrounding countryside as the animals cut down trees to use in their construction projects. Beavers build canals to transport heavy objects.
【小题1】What is Alaska’s Troop 34?

A．A team of the Boy Scouts.	B．An army.
C．A team of the Girl Scouts.	D．A sports team.

【小题2】Why does the troop hope to catch ten more beavers?

A．To fulfill their task.

B．To sell them for money.

C．To get enough fur.

D．To exchange them for mittens and hats.

【小题3】Which of the following statements is TRUE?

A．Sampson County has to find a new way to control the beaver population there.

B．The government program in Sampson County has proved to be a success.

C．The local government has controlled the number of beavers in the County.

D．More and more trappers now start to set traps in Sampson County.

【小题4】Local residents hate beavers because they can ___________.

A．cause damage to dams

B．block up canals with heavy objects.

C．do great harm to construction projects.

D．badly damage the environment and cause floods.

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.

【小题5】What does the underline word “screaming” in paragraph 4 mean?

A．哭喊声

B．令人惊愕的

C．尖叫声

D．尖叫的

An astronomer is making a case for launching pop singer Justin Bieber into suborbital（亚轨道的）space aboard a private rocket ship. The idea is not to rid the world of the Canadian teenager — he would come back down to Earth eventually, after all — but rather to help jump-start the emerging suborbital spaceflight industry.
It would generate a lot of public interest, which would help commercial spaceflight pick up some much-needed momentum, said Seth Shostak, senior astronomer at the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, California. “If there’s more interest, there are more customers. If there are more customers, there's more technical development. It's a positive feedback loop, and obviously that's good.”
Such missions would return to Earth without completing a full lap around the planet. Instead, the flights would hit the edge of space about 62 miles (100 kilometers) above Earth, experience a few minutes of weightlessness, then re-enter the atmosphere and land back at a spaceport.
None of these firms are ready to fly customers yet, but some are getting close. For instance, Virgin Galactic hopes to begin powered test flights of its SpaceShipTwo vehicle later this year, with commercial operations perhaps beginning in 2013 or 2014. It is SpaceShipTwo that reportedly grabbed the attention of Beyonce and Jay-Z.
Virgin Galactic has collected deposits from nearly 500 customers willing to pay $200,000 for a ride aboard SpaceShipTwo, and both Virgin and XCOR have inked deals to fly scientists and their experiments on research flights. So a suborbital market already exists — but Shostak is thinking about ways to make it grow.
A celebrity launch isn't Shostak’s only idea. Suborbital firms should also promote their activities aggressively via social media, Shostak said, and they should make sure their spaceships are bristling（充满）with cameras both inside and out, to give the public dramatic views of every mission.
Some observers view commercial suborbital spaceflight as a potentially transformative industry, saying it could serve as a stepping stone to the exploration and exploitation of space on an unprecedented scale. While the industry’s success is far from assured, Shostak offered some reason for optimism: The American public remains keen on space.
【小题1】Why may Justin Bieber be sent into suborbital space?

A．To show his bravery and make him a role model for teenagers.

B．To arouse the American public’s interest.

C．To help reform the spaceflight industry.

D．To film an advertisement about space.

【小题2】What can we learn about suborbital spaceflight?

A．A trip will return to Earth before finishing a lap.

B．The whole trip will leave passengers weightless.

C．Each trip can take 500 passengers.

D．The trip will be too expensive even for celebrities.

【小题3】What can we infer from the text?

A．SpaceShipTwo will be the first to fly.

B．Famous people will be the main passengers in the future.

C．The space trip is still in preparation.

D．Every space trip will be made into a film.

【小题4】The last paragraph suggests that _________.

A．space is too mysterious to explore

B．the suborbital market is promising

C．the spaceflight industry is more successful than people think

D．developing the industry is risky

【小题5】What is the main purpose of the text?

A．To predict a change in the space market.

B．To discuss a recent launch.

C．To introduce the status of the spaceflight industry.

D．To remove public doubt about the spaceflight industry.