题型:阅读选择 题类: 难易度:普通
广东省茂名市愉园中学等几校2023-2024学年八年级下学期第一次质量监测英语试题
Astronauts would face dangers both getting to and surviving (生存) on Mars. Let's learn about surviving a trip to Mars.
What would it take to keep people safe and healthy on a trip to Mars? Scientists are already working on it, though the trip may be many years later.
Over the last 60 years, many spaceships have flown by orbited(沿轨道运行)and even landed on the Red Planet. However, machines cannot replace humans. That's why the United States, China and other countries want to send people to Mars. But surviving on this trip would not be easy.
A trip to Mars would be the farthest journey in human(人类) history. Mars is about 225 million kilometers away, so it would take astronauts at least 180 days to reach there. However, it only takes a few days to get to the Moon.
Space travel is dangerous. For one thing, staying in space for long periods makes the human body weak. Also, it puts pressure behind the eyes and causes eye problems. But gravity(重力) machines could help.
Then there's space radiation(辐射) to worry about. It is bad for astronauts when they have long journeys. Scientists are working out the issue. They have found that taking certain vitamins can help.
Astronauts will have to pack light to lift off from the earth. But they won't be able to get the things they need easily. Astronauts on the space station practice for this by growing lettuce and other food in space. Engineers are developing 3D printing techniques(技术)which can allow future Mars astronauts to build what they want.
Man has invented four kinds of satellites(人造卫星).
The first kind of satellites studies the geography of the earth. They are used to make maps. They also help countries to see where they may find oil or gold. |
The second kind of satellites is used to guide ships and planes. A ship or a plane can send a message to the satellite, and the satellite can find out where the ship or the plane is. |
The third kind studies the weather. These satellites watch clouds and strong winds moving across the earth. They warn countries to make preparations when very bad weather is coming. |
The last kind is used for communications(通信). Telephone calls between countries can be sent. by these satellites. Some can carry hundreds of calls at the same time. The call is sent to the satellite, then the satellite' sends it to a station in the country and this country is being phoned. These satellites also carry pictures; they can receive and send about eight programmes at a time. |
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