There are two kinds of changes—chemical change and physical change.

In a chemical change, there is always a new substance(物质) formed. Breaking up water into hydrogen(氢气) and oxygen(氧气) is a chemical change. In each of the chemical change at least one new substance is formed. A change is not a chemical change if it doesn’t form a new substance.

Physical changes are very common, too. There are many examples. You can make a physical change by tearing(撕开)a piece of paper in two, or by cutting a piece of iron with lathe(车床). Here paper is still paper, and the iron is still iron.

Another way of making physical change is dissolving(融化) something in water. When you dissolve salt in water, the salt disappears. You may think that a new substance has been formed. But really there is no new substance. The salt is still salt. You can still taste it. So the dissolving of anything is a physical change.

When water freezes, the change is also a physical one. The water changes from liquid(液体) to solid(固体). But it is still the same substance. That is why the freezing of anything is a physical change.

1.It is not ______ if a new substance is not formed in the change.

A.a physical change                  B.a chemical change

C.change of state(状态)            D.a change

2.The dissolving of salt in water is _________.

A.a physical change                  B.a chemical change

C.hydrogen and oxygen             D.breaking up

3.Which is wrong according to the passage?

A.A new substance is always formed in a physical change.

B.Two kinds of changes are talked about in this passage.

C.If a change forms a new substance, it’s a chemical change.

D.The physical changes include the freezing of anything.


完形填空。

通读下列短文,然后从各题所给的四个选项中选出一个最佳选项。

Yesterday I read a report on a charity show in a local newspaper. The aim of the show was to 1 money for the poor children. In the poor areas, some children were out of school because their parents couldn’t 2 their education.

Many pop stars 3 the charity show, such as Andy Liu, Jay, Faye Wang and Kitty Chen. The stars didn’t ask for any pay. They did it for long! There were a lot of performances 4 singing and dancing. The audience(观众) were so 5 that they clapped their hands from time to time. Of course, the show was 6 .

All the people followed the stars’ example. They showed their generosity(慷慨)in 7 their money to the show. Both the ticket money and the donated money were soon sent to the poor areas and some of the poor children could get back to school.

Now many charity shows 8 in our country, not only to support the education in poor areas, but also to help people in trouble. As theng goes, “All the others will come to one’s rescue(援助) 9 one is in trouble.”

I 10 the whole world will become better and better.

( )1. A. raise

B. pay

C. spend

D. cost

( )2. A. pay for

B. pay

C. cost

D. get

( )3. A. took part in

B. joined

C. got to

D. had

( )4. A. for

B. of

C. as

D. like

( )5. A. exciting

B. excited

C. sad

D. surprised

( )6. A. boring

B. bad

C. successful

D. easy

( )7. A. bring

B. collecting

C. taking

D. donating

( )8. A. hold

B. are holding

C. are held

D. will be held

( )9. A. when

B. than

C. before

D. because

( )10. A. want

B. hope

C. love

D. wish

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