问题 解答题

快、慢两车从A、B两地同时相对开出,经过5小时相遇.相遇后两车继续按原速度行驶,又经过3小时快车到达B地,慢车距A地180千米,问A、B两地的公路长多少千米?

答案

快车走全程共用5+3=8(小时),

两车相遇后快车行的路程占全程的3÷8=

3
8

慢车1小时行的路程占全程的

3
8
÷5=
3
40

慢车8小时行的路程占全程的

3
40
×8=
3
5

A、B两地的公路长是:

180÷(1-

3
5
),

=180÷

2
5

=450(千米).

答:A、B两地的公路长450千米.

阅读理解

阅读理解。

     We each have a memory. That's why we can still remember things after a long time. Some people

have very good memories and they  can easily  learn many  things by heart, but some people can only

remember things when they say or do them again and again. Many of the great men of the world have

got surprising memories.

     A good memory is a great help in learning a language. Everybody learns his mother language when

he is a small child. He hears the sounds, remembers them and  then he learns to speak. Some children

are living with their parents in foreign countries. They can learn two languages as easily as one because

they hear, remember and speak two languages every day. In school it is not so easy to learn a foreign

language because the pupils have so little time for it, and they are busy with other subjects, too.

     But your memory will become better and better when you do more and more exercises.

1.Some people can easily learn many things by heart because .

A.they always sleep very well

B.they often eat good food

C.they read a lot of books

D.they have very good memories

2.Everybody learns his mother language .

A.at the age of six

B.when he is a small child

C.after he goes to school

D.when he can read and write

3.Before a child can speak, he must .

A.read and write

B.make sentences

C.hear and remember the sounds

D.think hard

4.In school the pupils can't learn a foreign language well because .

A.they have no good memories

B.they have no recorders

C.they have too much time for it

D.they are busy with other subjects

5.Your memory will become better and better .

A.if you have plenty of good food

B.if you do more and more exercises

C.if you do morning exercises every day

D.if you get up early

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