Scientists think that there _____ life on Ear...

Scientists think that there has been life on Earth for _______ years.

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完形填空

Scientists think that there 　　　 life on the earth for hundreds of millions of years. However, we have not found life on any other planets　　　　 .

The earth is a planet and it 　 　　　　 　　 around the sun. Seven other planets also go around the sun. 　　　　 of them has an environment like that of the earth, so scientists do not think they will find life on them. The sun and its planets are called the solar system, and our solar system is a small part of a much larger group of stars and planets, 　　 　 　 the Galaxy or the Milky Way.

There are billions of stars in the Galaxy, and our sun is only one of them.

Scientists have also discovered many other galaxies in the universe. They are very far away and their light has to travel for many years to reach us. So 　　 　 　　 is the universe? It is impossible to imagine.

Scientists have sent spaceships to the planet Mars　　 　 　　 . They have even

sent spaceships to travel outside the solar system. However, no spaceship has travelled 　 　 to reach other stars in our Galaxy.

Scientists have always asked the questions: with so many stars in the universe, are we　 　 　　 , or is there life out there in space? Have there been visitors to the earth from other planets? Why has　　 　 communicated with us? We do no know the answers... yet.

1.A. have been　　 　 B. has been　　　 C. is　　　　　 　　 D. are

2.A. yet　　　　　　 　　 B. already　　　　 C. just　　　　 　　 D. ever

3.A. go　　　　　　　 　　 B. went　　　　　 　 C. goes　　　　 　　 D. going

4.A. no one　　　　 　　 B. neither　　　　 C. either　　 　　 D. none

5.A. called　　　　　 　 B. call　　　　　　 C. to call　　　 　 D. calls

6.A. what large　　 　 B. how small　　　 C. how large　　 　 D. how long

7.A. to take photos B. take photos　　 C. taking photos　 D. takes photos

8.A. enough far　　　 B. enough near　　 C. far enough　　 D. near enough

9.A. lonely　　　　　　 B. alone　　　　　 C. along　　　　　 　 D. alonely

10.A. someone　　　　 B. anyone　　　　 C. somebody　　 　 D. no one

八年级英语完形填空简单题查看答案及解析

Scientists think that there _____ life on Earth for millions of years.

A. has had　　 B. have had

C. has been　　 D. have been

八年级英语单项填空中等难度题查看答案及解析

Scientists think there has been life on Earth for _______ years.

A. millions of　　 B. hundreds of　　 C. five million of　　 D. million of

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1

Scientists think that there has been life on Earth for 1 (百万) of years. However, we haven’t found life on other 2 (行星) yet. The earth, the moon, and the sun are a small part of our galaxy. Scientists have 3 ( 发现) many other galaxies in the universe. And there are many books about the universe. I’ve just finished 4 (看) a great book at school. It is a book about the solar system. It is so good that I’ve5(已经) asked the library to keep the next book for6 (我). In the book, it says that astronauts have 7 (去) to Mars and even to Jupiter. I’ve never read that before. I’ve 8 (写信) to NASA to ask them for9 （更多）information about astronauts and space. I hope they will write 10 (回) soon.

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Scientists think that there has been life for__31_ of years. However we haven’t found life on other planets _32_ . The earth is a planet and it _33__ around the sun. Seven other planets also go _34_ the sun. The sun and its planets are __35  the solar system. The solar system is a small part of our galaxy.

Scientists __36_ lots of spacecraft to look at other planets in the solar system, and some spacecraft have gone __37_ the solar system. However, no one __38_ any life in space yet.

But why has no one from other planets sent us a message ? Have they tried to send _39_ to us ? _40_so many stars in the universe, are we alone, or is there life out there in space ? We don’t know.

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—How many years has life been on earth?

—______ years, I think.

A. 5 millions　　　　　　　　　　　　　　　 B. 5 millions of

C. Million of　　　　　　　　　　　　　　　 D. Millions of

八年级英语单项填空中等难度题查看答案及解析

Is there intelligent (有智力的) life on other planets? For years, scientists said “No” or “We don’t know.” But today this is changing. Seth and Alex are astronomers (天文学家). They believe intelligent life exists (存在) somewhere in the universe They also think we will soon communicate with these beings (人, 生物).

Why do seth and Alex think intelligent life exists on other planets? The first reason (理由) is time. Scientists believe the universe is about 12 billion years old. “This is long enough for other planets to have intelligent life.” say Seth and Alex. The second reason is size. The universe is huge. “We have known that there are at least 100 billion galaxies.” says Seth, “And our galaxy, the Milky Way, has at least 100 billion stars. Some planets going around these stars might be similar (相似的) to Earth.”

In the past. it was hard to look for signs (迹象) of intelligent life in the universe. But now, powerful telescopes (高倍望远镜) allow scientists to discover smaller planets—the size of Mars or Earth—in other solar systems. These planets might have intelligent life.

Have beings from space already visited Earth? “Probably not.” says Alex. “It’s a long way away. However, intelligent beings may communicate with us in other ways, such as radio signals (信号). In fact, they may be trying to communicate with us now, but we don’t have the right tools (工具) to receive their messages. However, this is changing. By 2025, we could communicate with other life forms in our universe and we might help each other.”

1.Seth and Alex think ________.

A. intelligent life exists somewhere in the universe

B. it was easy to look for signs of intelligent life in the universe in the past

C. beings from space have already visited Earth

D. we have the right tools to receive other intelligent life’s messages

2.Scientists believe ________ may be long enough for other planets to have intelligent life.

A. 100 billion galaxies

B. 100 billion stars

C. about 12 billion years

D. the huge universe

3.Why is it easy to look for signs of intelligent life in the universe now?

A. There are more smaller planets.

B. There are some powerful telescopes.

C. The astronomers are more interested in them.

D. The Milky Way exists now.

4.Why haven’t we received other intelligent beings’ messages according to Alex?

A. They may not want to communicate with us now.

B. They don’t know how to send radio signals to us.

C. There isn’t intelligent life on other planets.

D. We don’t have the right tools to receive their messages.

5.This passage mainly talks about ________.

A. the size of Mars or Earth

B. intelligent life on other planet

C. other solar systems

D. the Milky Way

八年级英语阅读单选中等难度题查看答案及解析

Scientists believe that in the future there ______ a planet for humans to live on.

A. is　　 B. will be　　 C. is going to have　　 D. won’t have

八年级英语单选题中等难度题查看答案及解析

The question whether there is life on Mars (火星) has made the public think a lot for more than a century. The closest look showed Mars to be a dusty, cold world, covered by air too thin to breathe. A British spaceship and Europe's Mars spaceship plan to land on Mars or enter orbit (轨道) around it. One of the NASA’s (美国宇航局) spaceships is expected to land on January 3, the other is going to land on the opposite side of Mars on January 24. Since 1960, over twenty spaceships sent to Mars have failed. Most have been lost on flying up or landing because those are the most difficult times of any flights. Scientists wanted to find out whether there was water in Mars. In October, a team of scientists reported that Mars had been a dry wasteland. But weeks later, a second team reported differently that they had found some marks showed clearly that they were made by the rivers. Such marks told us that Mars was a warmer place billions of years ago — just as life first appeared here on Earth. Scientists at once raise a question: if what they said is true, what happened on Mars? Then what about the earth?

1.Which is right about Mars?

A.It’s cold without dust.

B.There is no water or air.

C.It’s warm with some thin air.

D.It’s a dusty, cold world almost without air.

2.Two NASA’s spaceships _______________.

A.will land on the different sides of Mars

B.will land on the same day

C.will enter orbit around Mars

D.will land with a man

3.The most difficult times of a flight are _______________.

A.taking off

B.flying up and arriving

C.entering the orbit and landing

D.leaving the earth and entering the orbit

4.A team of scientists reported that there might be_____________ in Mars.

A.nothing but air

B.nothing

C.water billions of years ago

D.thick air and lakes

5.What are scientists worried about when they raise the question?

A.Life disappeared on Mars.

B.Spaceships can’t land on Mars.

C.The air on the earth gets less and less.

D.The earth might be changed like Mars

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