题目内容

In the future, people may travel to Mars (火星) by water-powered spaceship! Today's spaceships are fine for getting things into space, but they are not so good at travelling long distances. These spaceships burn chemical fuels (燃料) and they are very expensive. Scientists say that a water-powered spaceship could make the trip to Mars much cheaper. The idea is just in the planning stages now, but scientists think such a spaceship could be developed soon.

The key to the water-powered spaceship is the engine (发动机). Regular engines push spaceships by burning fuel. The water engine will use steam, created by solar panels (太阳能板) that heat water to a high temperature. Of course, the spaceship will have to carry a lot of water for the long trip to Mars.

Today's spaceships could not carry that much water. But scientists think that a spaceship blown up like a balloon will be able to.

One US company has already developed a spaceship like this. These spaceships are made of a strong material. Two of them have already been sent up into space, using rockets and then later filled with air. "Balloon" spaceships could be very large and carry enough water for a long trip. With the "Balloon" spaceships, enough water could be carried to power the engines and grow food during the trip. And the people on the spaceship might even get to take a hot bath!

Scientists say the biggest advantage of such a spaceship would be cost. The "Balloon" spaceship uses water to push it through space and costs about one thirtieth of a normal spaceship. Such savings naturally encourage continued research into balloon spaceships and water engines. If these scientists are correct, we may soon be on our way to Mars in a spaceship powered by water.

1.Which sentence best describes the main idea of the passage above?

A.The key to the water-powered spaceship is the engine.

B.In the future, people may travel to Mars by water-powered spaceship.

C.One US company has already developed a spaceship like this.

D.Scientists say the biggest advantage of such a spaceship would be cost.

2.What do you think is omitted (省略) at the end of the underlined sentence?

A.use steam B.push spaceships

C.heat water D.carry that much water

3.Besides growing food, what else might astronauts do with the rest of the water?

A.Take a hot bath. B.Freeze dangerous things.

C.Blow up a balloon. D.Change the surface of Mars.

4.On which website can we probably read this passage?

A.www. freedictionary. com/power B.www. mooc. cn/music

C.www. chinadaily. com. cn/culture D.www. space. com/spaceflight

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It's late evening in the middle of the winter. The snow is deep, but off I go into the wild.

Suddenly, I hear it: the howl(嚎叫)of wolves. Excitedly, I walk faster in the direction of the howling.

I've been working as a volunteer wolf tracker in Yellowstone National Park for over a year It's my job to follow wolves to record information about them. Like wolves, however, I don't work alone. I'm one of a team of people who have been in a project to help reintroduce wolves to the park.

Humans have always feared wolves. From fairy tales to movies, the wolf is always the bad guy —a danger to humans and other animals. In the 1920s, the organizers of the park shared this view about wolves and made the decision to drive them away from the park. As a result, the number of elk (麋鹿)in the park increased. The elk started looking for food near river banks since they didn't have to worry about wolves. This, in turn, stopped trees from growing along the rivers, doing great harm to the environment there.

The return of wolves has already made a big difference. To begin with, the elk soon learned to stay away from the rivers, so new trees have been able to grow there. The trees become home to new wildlife, such as birds, and provide food for more animals.

The park is now becoming more and more popular with those who want to see wolves in their natural environment. It has also helped the local people make more money. Tourists visit the area, stay in the local hotels, and eat in the local restaurants.

Looking at the wild animals and the beautiful sceneries around me, I am amazed at the changes the wolf has made to Yellowstone. And happily, it is playing a good guy in this story.

1.According to the passage, one of a wolf tracker’s jobs is to________.

A.catch wolves in the park B.feed wolves in the wild

C.stop wolves from killing elk D.collect information about wolves

2.Why did the organizers drive the wolves away from the park in the 1920s?

A.The wolves were always howling at night.

B.The elk in the park were in danger of dying out.

C.The wolves had done great harm to the environment.

D.The park was thought to be unsafe with wolves around.

3.Paragraphs 4 and 5 are mainly about the _______ that wolves have brought to Yellowstone.

A.risks B.troubles C.changes D.competitions

4.What does the writer mean by the underlined sentence in the last paragraph?

A.Wolves are important to Yellowstone. B.Yellowstone has been home to wolves.

C.The wolf and the elk live in peace now. D.The number of wolves is growing fast.

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