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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

 

根据句子意思，从方框中选用恰当的单词或短语填空。

peaceful , heavily,told , come true,mine,to make, traffic, said, at the end of

1.Light music often makes people feel ________________.

2.They have already decided _________________ a good plan for the coming holidays.

3.He _______________me his telephone number yesterday, but I can’t find it now.

4.There is something wrong with your bike, please use_____________________.

5.It’s raining __________________, so we can’t have our sports meeting on time.

6.My parents always give me some pocket money ___________ the month.

7.The journey took a long time. There was a lot of _________________.

8.If you work harder, your dream will _______________ soon.

 

Scientists who study the climate are still arguing about how fast the earth is warming and how much it will warm, but they do agree that the earth is warming and that it will keep warming if we don’t do anything about it.

Scientists agree that the burning of fossil fuels (化石燃料) like oil and coal cause greenhouse gases to escape into the air and that these gases are causing most of the warming. Another cause is deforestation (cutting down trees) . Trees soak up carbon dioxide, one of the greenhouse gases, from the air.

There are already some changes happening because of global warming. Sea level is rising and some animals are already moving to new homes. It’s already too late to stop global warming completely.

If the warming gets worse, as scientists expect, there may be some kinds of plants and animals that is disappearing because they can’t move to new homes. There may be more storms and floods. Sea level may rise so much that people have to move away from the coasts. Some areas may become too dry for farming.

Global warming is a very difficult problem to fix. People are having a hard time agreeing on what to do about it. For example, everyone agrees that wasting energy is a bad thing to do. But some people think that the federal government (联邦政府) should make laws about it, while other people think it should be up to each person or business to decide what to do.

Many states and businesses in the United States are not waiting until the federal government decides what to do. They have already started working on the problem.

1.What are the scientists arguing about in the passage?

A. How fast is the earth warming?                  B. How much will the earth warm?

C. The earth will keep warming if we don’t do anything about it.    D. Both A and B.

2.What does the underlined phrase “soak up” mean?

A．take in            B．grow up           C．take off           D．set up

3.What may be the causes of global warming?

A．The disappearance of plants and animals and the wasting energy.

B．The burning of fossil fuels and storms and floods.

C．The burning of fossil fuels and deforestation.

D．The rising of sea level and deforestation.

4.What is the best title of this passage?

A．The reason for global warming             B．How to stop global warming

C．The changes to the world                 D．The global warming

 

根据句子意思，从方框中选用恰当的单词或短语填空。

peaceful , heavily,told , come true,mine,to make, traffic, said, at the end of

【小题1】Light music often makes people feel ________________.
【小题2】They have already decided _________________ a good plan for the coming holidays.
【小题3】He _______________me his telephone number yesterday, but I can’t find it now.
【小题4】There is something wrong with your bike, please use_____________________.
【小题5】It’s raining __________________, so we can’t have our sports meeting on time.
【小题6】My parents always give me some pocket money ___________ the month.
【小题7】The journey took a long time. There was a lot of _________________.
【小题8】If you work harder, your dream will _______________ soon.

They have already been to the place ____ their ancestors lived .

A. which        B. where         C. when