修改时间：2021-05-20 浏览次数：429 类型：单元试卷
Man has 1 four kinds of satellites. The first kind of satellites studies the 2 of the earth. They are used to make maps. They also help countries to see 3 they can find oil or gold.
The second kind of satellites is used to guide 4 and planes. A ship or a plane can 5 a message to the satellite, and the satellite can find out where it is. The third kind of satellites studies the 6 . These satellites watch clouds and strong winds 7 across the earth. They warn countries to make preparations when very 8 weather is coming. They take photos of the earth from miles above it and send the photos to weather 9 on the ground. The last kind is used for 10 .Telephone calls 11 countries can be sent by these satellites. Some can carry hundreds of 12 at one time. The call is sent to the satellite and then the satellite send it to the station in the country 13 is being phoned. These satellites also carry 14 , they can send about eight programs 15 .
When man began to search the skies, he saw a lot of things. In the universe, the earth seemed to be just a small bit of dust. It is only a small planet, and travels around the sun. The sun together with its planets, travels in the Milky Way（银河）, our galaxy（星系）. The Milky way has about thirty billion stars like our sun, and is one of about a hundred million galaxies in the universe. Because the space is so great, it is difficult to work out how far away a star is. Instead of kilometers, we have light years. A light year means the distance light travels in one year. Our nearest neighbour galaxy is more than 9,000,000 light years away from the earth.
John went to the planet Mars for his holiday. This is his holiday.
Monday
We arrived in the Mars City at 4:30 in the afternoon (Mars time) by a space shuttle. We went to the Mars Hotel (five stars) for dinner before going to bed. I was very tired after the journey (it takes 72 hours to get there) , but I am looking forward to my holiday very much.
Tuesday
I didn't sleep well because of the weightlessness(), the gravity is only about three-eighths of that on Earth. I hit my head on the bedroom ceiling several times. After breakfast we spent the morning on the Mars farm. They don't use earth or chemicals to grow their food. We had lunch on the farm and then had a hoverbus ride over the Mars City. That was very exciting. In the evening we went shopping in the Mars City Shopping Mall. I bought some souvenirs for my family and my friends.
Americans love cars. They go everywhere in them. 85% of people in the US go to and form work by car. And most adults have driving licenses. Why does this car culture exist?
How it started
America's love of cars started after the war when soldiers returned home from World War Π to rebuild their lives. They borrowed money from the government to buy houses and cars which became the symbols of status（地位）. The more money they had, the bigger their cars were.
Making of roads
During the war, President Eisenhower noticed what good roads Germany had. He decided to build new four-lane（四车道）roads in America. He said is something happened suddenly, the two-lane roads wouldn't be able to carry all the cars that would suddenly leave the cities. Car and oil companies liked his idea and building started.
Car lovers
Not just teenagers are crazy about cars. Some Americans love their cars so much that they paint their cars beautifully. These are called Art Cars. Every April there is an activity in Houston, Texas, where they show their cars.
Pollution
Cars have polluted the environment. American President Bush refused a worldwide law that is against pollution. Many countries were angry about it. Bush said he had to think of the American economy（经济）and all the American people that make money from cars. Factories say they want to make cars that pollute less. But others say making cars that pollute less will never be as good as having fewer cars.
Have you ever thought of living on Mars? Our Earth is becoming more and more c. And at the same time there's terrible p here. If we move to Mars, things will probably change. However, it may be d for people to have a conversation there, because sound doesn't travel very f on Mars. The low pressure(气压) makes it so. For example, as by a human scream on Earth can travel a little over a kilometre. But on Mars, the sound from that same scream will only move 15 metres at m. Besides, the atmosphere on Mars is also much t than that on Earth. On Earth, our atmosphere is about 3 km t, while it is very thin on Mars. Also Earth has a much higher t than Mars. while it is very thin on Marsso, are you r to go to Mars?
目前，地球正面临着前所未有的危机，人口增多，能源减少，到太空生活成了热门话题。Daniel和他的同学讨论了在火星上生活的利弊，请根据讨论结果并加上自己的观点写一篇报道。
Advantages | Disadvantages |
interesting go to online schools much more space robot ( do work for us) things are cheap | get ill from living there far from Earth no food, water or oxygen some dangerous aliens easily float away |
Life on Mars
Life on Mars is different from that on Earth. Some students think it is better to live on Mars than on earth because……
试题篮
