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 Shostak and Alexandra Barnett are astronomers(天文學(xué)家). They believe intelligent life exists (存在) somewhere in the universe. They also think we sill soon contact these beings(人；生物).

Why do Shostak and Barnett think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. “This is long enough for other planets to have intelligent life,” say Shostak and Barnett. The second reason is size—the universe is huge. “Tools like the Hubble Telescope(哈勃望遠(yuǎn)鏡) have shown that there are at least 100 billion galaxies,” says Shostak. “And our galaxy, the Milky Way, has at least 100 billion stars. Some planets going around these stars might be similar to Earth.”

In the past, it was hard to look for signs of intelligent life in the universe. But now, powerful telescopes 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 Shostak. “It’s a long way away. However, intelligent beings may contact us in other way, such as radio signals(信號). In fact, they may be trying to communicate with us now, but we don’t have the right tools to receive their messages. However, this is changing. By 2025, we could make contact with other life forms in our universe and we might help each other.”

1. Seth Shostak and Alexandra Barnett are _____.

A. astronomers B. farmers C. singers D. drivers

2.What is the best title for Paragraph 2?

A. The Age and Size of Earth.

B. Our Galaxy: The Milky Way

C. Why Intelligent Life Might Exist.

D. Earth: The Only Planet with Intelligent Life

3.Why was it hard to look for signs of intelligent life in the universe in the past?

A. There were not any smaller planets.

B. There were not any powerful telescopes.

C. The astronomers were not interested in them.

D. The Milky Way didn’t exist at that time.

4. Why haven’t beings from space visited us yet according to Shostak?

A. They’re afraid of us.

B. It’s a long way away.

C. They don’t want to see us.

D. They don’t know how to use radio signals.

5.What does the underlined phrase “l(fā)ife forms” in the last paragraph mean?

A. Messages B. Tools

C. Intelligent beings D. Radio signals

練習(xí)冊系列答案
相關(guān)習(xí)題

科目：初中英語 來源：2015-2016學(xué)年江蘇鹽城東臺第一教研片八年級下一次月考英語卷（解析版） 題型：其他題

補(bǔ)全短文

Mr Brown went swimming with his friends one afternoon. They all put on their swimming trunks(游泳褲)except him because he t1. there would be some p2. for the swimmers to change clothes near the beach. However, when they got to the beach , he f3. nowhere to change clothes. So Mr Brown had to go to a car and changed his clothes in it. But while Mr Brown was p4. on his swimming trunks , an old woman c5. near and stood by the car. Mr Brown h6. to be quiet. Then he o7. the door of the car and shouted a8. to the woman ,”Do you always w9. people change their clothes?’ The woman shook her head and said ,”Do you always change your clothes in o10. people’s car?”

查看答案和解析>>

科目：初中英語 來源：2015-2016學(xué)年湖北武漢黃陂區(qū)部分學(xué)校八年級3月月考英語試卷（解析版） 題型：單項(xiàng)填空

The child isn’t old enough to _____ himself.

A. wear B. put on C. dress D. in

查看答案和解析>>

科目：初中英語 來源：2015-2016學(xué)年福建永春第七中學(xué)七年級下學(xué)期一次月考英語試卷（解析版） 題型：單項(xiàng)填空

I’m __________ my wallet, but I can’t _________ it.

A. looking for; look for B. finding; find

C. finding; look for D. looking for; find

查看答案和解析>>

科目：初中英語 來源：2016屆浙江杭州高橋初中教育集團(tuán)九年級下學(xué)期二次質(zhì)檢英語卷（解析版） 題型：單詞拼寫

單詞拼寫

根據(jù)下列句子及所給首字母，寫出各單詞的完全形式（每空限填一詞）。

1.Many forget that saving the earth begins w_______ small things.

2.It’s time for lunch. The students all r________ out of the classroom.

3.They called the police because the two women had s________ some shoes in their shop.

4.Most teenagers think they are old enough to make their own d________.

5.The famous doctor gave us some s_________ about how to keep healthy.

6.What’s w________ with him?. He looks so sad.

7.The next day, Peter went to soccer practice with courage r________ than fear in his heart.

8.U________, my bad luck turned into a good thing.

9.Do you have anything v________ in your schoolbag like iphones that cost much?

10.My classmates are working much h________ because we’ll take an important exam at the end of this term.

查看答案和解析>>

科目：初中英語 來源：2015-2016學(xué)年江蘇江陰山觀第二中學(xué)八年級3月月考英語試卷（解析版） 題型：補(bǔ)充句子

動詞填空用括號內(nèi)所給動詞的適當(dāng)形式填空。

1.--- What do you think of the story? --- It’s great! I ___________________ (read) it again.

2.After Sam finished the letter, he sat there silently, _____________(not know) what to do next.

3.Lei Feng always did what he could _______________ (help) people in need.

4.They will come to see him if it ____________ (not be) rainy tomorrow.

5.We ____________ (enjoy) our trip very much. It was great fun!

6.John couldn’t stop ______________ (laugh) when he heard the joke.

7.There _______________ (be) great changes in Wuxi in the past few years.

8.This is the most terrible film I __________( see). I don’t want to see it any more.

查看答案和解析>>

科目：初中英語 來源：2015-2016學(xué)年江蘇江陰山觀第二中學(xué)八年級3月月考英語試卷（解析版） 題型：單項(xiàng)填空

-----We are going to Jiuzhaigou this summer. ------ ________________.

A. Have a good time B. Help yourselves

C. I hope so. D. That’s right.

查看答案和解析>>

科目：初中英語 來源：2016屆江西崇仁第二中學(xué)九年級下學(xué)期第一次模擬測英語試卷（解析版） 題型：閱讀理解

What would the world be like if cars could drive themselves? Imagine seeing an empty car passing by on its way to pick up its owner, or a car full of passengers who are reading, listening to music or even sleeping, but none of them are worried about the road ahead.

Well, all of this could be the future of driving. There are several companies, including Google, working on driverless (無人駕駛的) cars, which are currently in the testing stages. If the tests are successful, these electric, self-driven cars could be available very soon. But, how is it possible for a car to drive itself?

Cars already have many features allowing them to take over for drivers in certain situations. Some features include cars being able to park themselves, or slow down when they detect objects (物體) close by. They can also control the speed if there are dangerous conditions, such as snow or slippery (滑的) roads.

Other features have also changed the way drivers react to some situations. Scientists and engineers believe, with the help of wireless signals, cameras and GPS, we are now at a stage where creating a safe self-driving car might be possible.

The self-driven car may be the answer to lowering the number of deadly (致命的) accidents caused by careless drivers or dangerous conditions. However, there are still some people who do not like the idea. American lawyer Whit Drake, for example, doesn’t believe these cars are safe. He thinks the possibility of the technology making a mistake will be too high.

1.What does the underlined phrase “take over for” in Paragraph 3 mean?

A. direct the way for B. take the place of

C. work better than D. make use of

2.Cars already have the following features EXCEPT ________.

A. parking itself

B. controlling its speed in dangerous situations

C. slowing itself down near an object

D. avoiding car accidents one hundred percent

3.Scientists and engineers think that ________.

A. it’s possible to make safe self-driven cars

B. it’s a long way for self-driven cars

C. there will be no drivers in the future

D. self-driven cars may cause more accidents

4.What does the article mainly talk about?

A. Advantages of self-driven cars.

B. Different opinions on self-driven cars.

C. Possibilities of self-driven cars.

D. Google’s new technology—self-driven cars.

查看答案和解析>>

科目：初中英語 來源：2015-2016學(xué)年四川巴中巴州區(qū)七年級下學(xué)期一次月考英語卷（解析版） 題型：閱讀理解

All students need to have good study habits(習(xí)慣 ).If you have good study habits, you can learn things quickly. You also remember easily

Do you like to study in the living room? This is not a good place because it is usually too noisy. You need to study in a quiet place, like your bedroom. A quite place will help you only think about one thing, and you will learn better.

Before you begin to study, do not forget to clean your desk. A good light is important, too. You’ll feel tired easily if there is not enough light(光線). So you should have a clean and bright lamp(燈).

1. If you have good study habits, you will_______.

A. learn things quickly

B. remember things easily

C. both A and B

2.The living room is not a good place for study because it is too_______.

A. quiet B. noisy C. clean

3. You are feeling tired easily if the light is _______.

A. good B. enough C. bad

4.You should remember to _______before you study.

A. clean the desk

B. tidy the room

C. turn the light

5.The best title(題目) for the passage is “_______”.

A. Good Study Habits

B. How to Study

C. Light is Important

查看答案和解析>>

同步練習(xí)冊答案