It’s5:00inthemorningwhentheala-优题课

Could we "terraform" Mars—that is, change its frozen, thinaired surface into something more friendly and Earthlike? Should we? The first question has a clear answer: Yes, we probably could. Spacecraft, including the ones now exploring Mars, have found evidence that it was warm in its youth，with rivers flowing into vast seas. And right here on Earth, we've learned how to warm a planet: just add greenhouse gases to its atmosphere. Much of the CO₂ that once warmed Mars is probably still there，in frozen dirt and polar ice caps, and so is the water.
Most of the work in terraforming，says NASA scientist Chris Mackay, would be done by life itself. "You don't build Mars," Mackay says. "You just warm it up and throw some seeds." Powerful greenhouse gases could be produced from elements in dirt and air on Mars and blown into the atmosphere； by warming the planet, they would release the frozen CO₂ , which would quicken the warming and increase atmospheric pressure to the point where liquid water could flow. Meanwhile, says botanist James Graham of the University of Wisconsin, human settlers could seed the red rock with a succession (系列) of ecosystems, first bacteria and lichens (地衣)，which survive in Antarctica, later mosses (苔藓)，and after one thousand years or so，redwoods. Getting breathable oxygen levels out of those forests，though，could take thousands of years.
However, Mars is in no immediate danger. Some space scientists recently recommended going to the moon or an asteroid (小行星)first，and pointed out the space agency lacks the funds to go anywhere. It didn't estimate the cost of gardening a dead planet.
What is the most essential to make Mars fit for living?

A．Turn ice into flowing water.

B．Clean the dirty atmosphere.

C．Make the atmosphere more suitable.

D．Go to the moon or an asteroid first.

What does the author think of the idea of terraforming Mars?

A．We could do it.	B．We couldn't do it.
C．We should do it.	D．We shouldn't do it.

In the botanist's opinion, man needs to ______ .

A．enable Mars to clean its atmosphere

B．build a greenhouse on Mars

C．send some people to settle on Mars

D．cultivate ecosystems from lower to higher life form

What is the best title for the passage?

A．Making Mars the New Earth.

B．A Good Way to Change the Universe.

C．Humans' Great Power.

D．Terrible Science and Technology.

We already know the fastest, least expensive way to slow climate change ： Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets.
Not long ago， my wife，PJ， and I tried a new diet—not to lose a little weight but to answer an annoying question about climate change. Scientists have reported recently that the world is heating up even faster than predicted only a few years ago，and that the consequences could be severe if we don't keep reducing emissions (排放)of carbon dioxide ( CO₂) and other greenhouse gases that are trapping heat in our atmosphere.
We decided to try an experiment. For one month we recorded our personal emissions of CO₂. We wanted to see how much we could cut back, so we went on a strict diet. The average US household produces about 150 pounds of CO₂ a day by doing commonplace things like turning on air conditioning or driving cars. That's more than twice the European average and almost five times the global average, mostly because Americans drive more and have bigger houses. But how much should we try to reduce?
For an answer, I checked with Tim Flannery, author of The Weather Makers： How Man Is Changing the Climate and What It Means for Life on Earth. In his book， he had challenged readers to make deep cuts in personal emissions to keep the world from reaching extremely important tipping points, such as the melting of the ice sheets in Greenland or West Antarctica. "To stay below that point, we need to reduce CO₂ emissions by 80 percent," he said.
Good advice, I thought. I'd opened our bedroom windows to let in the wind. We'd gotten so used to keeping our air conditioning going around the clock. I'd almost forgotten the windows even opened. We should not let this happen again. It's time for us to change our habits if necessary.
Why did the author and his wife try a new diet?

A．To take special kinds of food.

B．To respond to climate change.

C．To lose weight.

D．To improve their health.

The underlined words "tipping points" most probably refer to ______ .

A．freezing points	B．burning points
C．melting points	D．boiling points

It can be inferred from the passage that ______ .

A．it is necessary to keep the air conditioning on all the time

B．it seems possible for every household to cut emissions of CO₂

C．the average US household produces about 3,000 pounds of CO₂ a month

D．the average European household produces about 1, 000 pounds of CO₂ a month

Which of the following would be the best title for this passage?

A．Saving Energy Starts at Home

B．Changing Our Habits Begins at Work

C．Changing Climate Sounds Reasonable

D．Reducing Emissions of CO₂ Proves Difficult

Let These Plants Swat the Bugs for You Some plants get so hungry that they eat flies，spiders, and even small frogs. What's more amazing is that these plants occur naturally (in special environments) in every state. In fact, they're found on every continent except Antarctica.
You've probably seen a Venus' flytrap. It's often sold in museum gift stores, department stores, and even supermarkets. A small plant，it grows 6 to 8 inches tall in a container. At the end of its stalks (are specially modified leaves that act like traps. Inside each trap is a lining of tiny trigger (触发)hairs. When an insect lands on them, the trap suddenly shut. Over the course of a week or so, the plant feeds on its catch.
The Venus' flytrap is just one of more than 500 species of meat-eating plants， says Barry Meyers-Rice ， the editor of the International Carnivorous Plant Society's Newsletter. Note： Despite any science-fiction stories (科幻小说)you might have read, no meat-eating plant does any danger to humans.
Dr. Meyers-Rice says a plant is meat-eating, only if it does all four of the following："attract, kill, digest, and absorb" some form of insect, including flies, butterflies, and moths. Meat-eating plants look and act like other green plants—well, most of the time.
All green plants make sugar through a process called photosynthesis (光合作用). Plants use the sugar to make food. What makes "meat-eating" plants different is their bug-catching leaves. They need insects for one reason ： nitrogen (氮). Nitrogen is a nutrient that they can't obtain any other way. Why?
Almost all green plants on our planet get nitrogen from the soil. "Meat-eating" plants can't. They live in places where nutrients are hard or almost impossible to get from the soil because of its acidity (酸度). So they've come to rely on getting nitrogen from insects and small animals. In fact, nutrient-rich soil is poisonous to "meat-eating" plants. Never fertilize (施肥)them! But don't worry, either, if they never seem to catch any insects. They can survive, but they'll grow very slowly.
Venus flytrap ______.

A．is a small plant which grows in a container

B．is a kind of plant which gets hungry easily

C．can attract, kill， digest and absorb some form of insects

D．grows 6—8 inches tall

From the passage, we know ______.

A．"meat-eating" plants are found on every continent

B．all green plants get nitrogen from the soil

C．bug-catching leaves make "meat-eating" different from other plants

D．some "meat-eating" plants in the rainforest do danger to humans

"Meat-eating" plants grow very slowly, ______.

A．so you'd better fertilize them

B．probably because the source of nitrogen is cut off

C．simply because they can't absorb nitrogen from the soil

D．and then they will die slowly

Which of the following is true?

A．"Meat-eating" plants look and act like other green plants.

B．No insects, no "meat-eating" plants.

C．The reason why Venus flytrap needs flies is that it needs to get nutrient from them.

D．Green plants make sugar at night.

LONDON, England (CNN) —The youngest person to sail solo around the world returned home Thursday from his 30,000-mile, 282-dav ocean journey.
Mike Perham, 17 , sailed into Lizard Point in Cornwall, the southernmost point in Britain, at 9:47 a. m.，his race team said.
" It feels absolutely brilliant," Mike told CNN by phone hours before crossing the finish line. "I'm really, really excited to be going across the line at last. It doesn't feel like long since I crossed it first."
Mike set off on his round-the-world trip on November 18， 2008. He has been sailing his yacht single-handedly, though a support team has been sailing next to him along the way.
The teen has now achieved the title of Youngest Sailor to Circumnavigate the Globe Solo, according to the Guinness World Records.
Mike learned how to sail when he was seven years old from his father, Peter and at age 14，he sailed across the Atlantic alone.
The teenager's school—which Mike describes as "highly supportive" of his trip—has redesigned his coursework to fit in with his trip. It also gave him some coursework to do during "quiet moments," according to Mike's Web site.
There haven't been many of those quiet moments. Repeated autopilot failures forced him to stop for repairs in Portugal, the Canary Islands，South Africa，and twice in Australia，according to his Web site.
Bad weather in the Southern Ocean—between Australia and Antarctica—forced Mike to battle 50ft waves and 57 mph winds. He said at one point，a "freak wave" picked up the boat and turned it on its side.
"My feet were on the ceiling at the time，" he told CNN. "That was a really hairy moment， and I was certainly thinking， 'Why am I here? ’ But we took the sails off and the day after I thought/This is brilliant!’"
Mike describes his father as his biggest hero，always supportive of what he wanted to achieve. Peter Perham said he wasn't too worried about his son facing dangerous situations at sea, as long as he knew what to do and stayed safe.
Mike Perham returned to Britain in ______ .

A．August	B．September
C．October	D．November

Mike Perham is ______ that went on the round-the-world trip in the world up till now.

A．the first	B．the bravest
C．the luckiest	D．the youngest.

We can infer from the passage that ______ .

A．the English school is the same as ours

B．the English school doesn't care for students

C．the English school has a humane management

D．the English school gives students a lot of course work

The passage mainly tells us ______ .

A．Mike's exciting sail trip around the globe

B．how Mike's father taught him to sail a boat

C．why CNN wanted to report the news to the public

D．the introduction of the Guinness World Records

Polar bears depend on ice to hunt (猎取)for food in the Arctic Ocean. They climb up on the ice to look for seals and other animals. But scientists say sea ice is decreasing (减少)because of climate change. They say rising temperatures have reduced the area in which polar bears can hunt.
Recently, a number of studies found that future reductions of sea ice could result in a loss of many polar bears within fifty years. The studies found a direct link between sea ice in the Arctic Ocean and the health of polar bears. The scientists say the animals will disappear from the north coasts of Alaska and Russia in the next fifty years. The only polar bears to survive will be in Canada's far north and the west coast of Greenland.
The scientists found that almost two thirds of the world's nineteen polar bear populations will disappear from the earth by the middle of this century. The studies showed that three more groups of polar bears will disappear within seventy-five years.
Scientists say polar bears still can be saved. But they say the world must begin taking steps to reduce climate change to do this. The center for Biological Diversity says governments around the world need to reduce the release (释放)of pollution like C02 gas.
Scientists say one step toward this goal would be to include polar bears on America's list of endangered species. Then the government would be able to make sure that industrial activities do not threaten their survival. The United States Fish and Wildlife Service is expected to examine the new findings when it considers whether polar bears should be included on the Endangered Species List.
Which of the following is TRUE according to the passage?

A．The living conditions of the polar bears are improving.

B．Almost two thirds of polar bears will disappear within seventy-five years.

C．The health of polar bears is directly connected with the sea ice.

D．The polar bears mainly feed on sea ice.

According to the passage, the number of the polar bears is directly decided by ______.

A．the climate change	B．the amount of sea ice
C．C02 gas	D．industrial activities

Whether polar bears should be included on America's Endangered Species List or not is decided by ______.

A．the United States Fish and Wildlife Service

B．the Center for Biological Diversity

C．the polar bears themselves

D．American government

This passage mainly tells us ______ .

A．the relationship between climate change and sea ice in the Arctic Ocean.

B．the influence of the weather change on the polar bears in the Arctic Ocean.

C．one step to save the endangered polar bears.

D．the fact that the number of the polar bears is decreasing.