问题 多选题
一列简谐横波沿x轴正方向传播,传播速度为10m/s.当波传到x=5m处的质点P时,波形如图所示.则以下判断正确的是(  )

A.这列波的周期为0.4s

B.再经过0.4s,质点P第一次回到平衡位置

C.再经过0.7s,x=9m处的质点Q到达波峰处

D.质点Q到达波峰时,质点P恰好到达波谷处

答案

AC

阅读理解

阅读理解。

     Many people often lose their friends and they don't know how to keep a long friendship.So

how can you keep a long friendship? The following passage explains very well about this matter.

     The first thing you need to do is to become a good listener.In this way,you show your friends

that you are interested in their lives.You want to know more about them and you want to help

them solve their problems.They will cherish the friendship more if they know you care about them.

     The next thing is that you should respect other people's privacy (隐私).People usually don't

like others to know about their private life,so you should show respect toward their privacy.

Sometimes,they need some suggestions from others,but this does not mean that others can know

about their entire life.So respect for privacy is a must for keeping a long friendship.

     The third important thing is that you need to be able to forgive.You must remember that nobody

 is perfect in this world.It is important to forgive others and not to blame them for the mistakes they

have already made.You are not perfect either.Thus you need to apologize to others for the mistakes

you may have made.

     Pay attention to the three things above,and you will be able to have long friendships.

1.This passage is written to tell us________.

A.why a long friendship is important

B.what we can do for our friends

C.how to make friends with others

D.how to keep a long friendship

2.According to the passage,what is the first thing that we need to do?

A.To know more about our friends.

B.To share our happiness and sadness.

C.To be good at listening to our friends.

D.To help our friends solve their problems.

3.From Paragraph 3 we know that________.

A.we should never share our private lives with others

B.some people never care about their privacy

C.it is important to respect other people's privacy

D.some people like sharing their privacy

4.What does the writer suggest you do if your friend makes a mistake?

A.Blame him.      

B.Forgive him.

C.Tell him why it is so.      

D.Leave him immediately.

5.The writer most probably thinks that________.

A.everyone makes mistakes

B.some people are perfect

C.people often make stupid mistakes

D.we shouldn't apologize fpr every mistake

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