21.It's our duty to do sth. 做什么事是我们的责任. 查看更多

 

题目列表(包括答案和解析)

Three kids have been learning chemistry for only a few months. But they have already begun to challenge (挑战) a world famous scientist!

Li Weichi, Huang Runling, and Xiao Yan are from Zhongshan Huaqiao Middle School in Guangdong. They have just found a red cabbage that could be a new kind of acid-base indicator (酸碱指示剂). They want it to take the place of litmus (石蕊) paper.

"We've learnt to think of and ask questions about life by ourselves," said Li, "We work well with each other."

British scientist Robert Boyle discovered the use of litmus paper over 300 years ago. Now it is used widely in experiments all over the world.

But when the kids did some experiments in class last winter, they saw that the litmus paper didn’t turn very blue with base matter. It's hard to get a clear result.

Will there be a better indicator than litmus paper? The three kids decided to try and find out!

How? They went to collect over 40 plants in parks, gardens and markets. Then they ground (研磨) leaves, flowers and stems (茎) to get the pigments (色素) from them.

The kids mixed pigments with acid and base. They spent months watching carefully to see which paper showed the best color change. They decided it was the litmus paper!

"It's our first scientific journey, Huang said, "But it makes me want to try harder."

1.Whom did the three kids want to challenge?

A. Their chemistry teacher.

B. Their headmaster.

C. Robert Boyle

D. Thomas Edison

2.From the text, a red cabbage is a kind of ____.

A. plant  B. animal  C. paper  D. liquid

3.What is widely used as the acid-base indicator now?

A. red cabbage              B. litmus paper

C. any plant                D. any flower 

4.The story mainly tells us ____.

A. how to make litmus paper

B. about the three kids' spirit

C. scientists were wrong

D. the kids are heroes

 

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-Our classroom__________ every day.

-So it is. It’s our duty to keep it clean and tidy.

A. cleans              B. is cleaning         C. is cleaned

 

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阅读短文,判断下列句子是否符合短文内容。符合的写“A”,不符合的写“B”。

Water is the most important in our lives. Not Many people understand this but it’s quite true. The human body can go without food for a long time. We’ve got many examples for this. Yet two or three dayswithout water can usually make people die. Man can’t live without water.
Many people don’t understand how much water the human body needs to work well, and many people, especially young people, do not drink enough water, even in very hot weather. About two thirds of our body is water. When we do sports, some of the water will get away from our body. If we don’t drink some water, our body won’t have enough water. And if we don’t have enough water, we’ll feel tired and many of us will get ill. So you know how important water is to us.
But at present we face water crisis(危机). Water is becoming less and less. So, we should protect water resources(资源) and try our best to save water in our daily life. Here are some tips for saving water:
1. Turn off the tap(水龙头) in lime.
2. Take shorter showers.
3. Don’t let water run while washing your face and reuse the water after we finish washing.
4. Encourage your friends and neighbors to join in the action of saving water.
【小题1】 Nobody can live without water.
【小题2】 About one third of our body is water
【小题3】 If one doesn't have enough water, he’ll feel tired and may get ill.
【小题4】 We’d better take longer showers and let water run while washing.
【小题5】 It’s our duty to protect water resources and save water.

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In the universe,there is the earth,the moon,the sun,the stars and all the other things too far away to see.The earth is one of the sun’s   ,and the moon is our satellite.The moon is about three hundred and eighty thousand kilometers away 2   the earth ,but it’s our 3 neighbor in space.It 4  more than three days to get there by spaceship No man 5  fathar than the moon ,but spaceship 6  people has reached other planets.

Of  7   the stars ,the sun is the nearest to the earth  8    other stars are even bigger and brighter than the sun.They look small only 9  they are much farther away.You 10  see them in the daytime .But if you go out at night ,you’ll be able to see many of them.

1.

A.Stars

B.planets

C.satellites

D.planet

 

2.

A.over

B.below

C.down

D.from

 

3.

A.nearer

B.the nearer

C.nearest

D.the nearest

 

4.

A.takes

B.took

C.taken

D.taking

 

5.

A.travel

B.travelled

C.has travelled

D.have travelled

 

6.

A.with

B.without

C.for

D.to

 

7.

A.all

B.some

C.many

D.any

 

8.

A.Thousand of

B.Hundred of

C.Million of

D.Millions of

 

9.

A.when

B.because

C.if

D.for

 

10.

A.must

B.mustn’t

C.can

D.can’t

 

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用所给词的适当形式填空

1.It was half past ten,and I __________( lie)in bed reading.

2.It’s our duty for our students _________(raise)money for the Project Hope.

3.The mother looked _______(angry)at her naughty daughter.

4.There are ______(million)of people watching the basketball match at home.

5.Lily______(enter)the English competition before so she has much experience.

6.Do you want to know If he ______(win)the prize next time?

7.Have you got anything interesting in ______(today) newspaper?

8.Classes must be over. Because the students ______(play)on the playground.

9.The Language Doctor gives us some ______(advise) on how to learn English.

10.Sam is very shy when he____(have)to speak to the foreigner

 

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