问题 问答题 简答题

带状切削产生的条件有哪些?

答案

参考答案:

加工塑性金属材料,切削速度较高,切削厚度较簿,刀具前角较大,由于切屑前切滑移过程中滑移量较小,没有达到材料的破坏程度,因此形成带状切屑。

阅读理解

阅读理解。

     If you do not use your arms or your legs for some time, they will become weak. When you start using

them again, they slowly become strong again. Everybody knows that.  Yet many people do not seem to

know that memory works in the same way.

     When someone says  that he   has a good memory,    he really means that he   keeps  his memory in

practice by using it. When someone else says that his memory is poor, he really means that he does not

give it enough chance to become strong.

     If a friend says that his arms and legs are weak, we know that it is his own fault(过错). But if he tells

us that he has a poor memory, many of us think that his parents may be blamed(责 备),  and  few of us

know that it is just his own fault. Have you ever found  that  some people can't  read or write but usually

they have better memories ? This is because they cannot read or write and they have to remember things,

they cannot write them  down  in  a small notebook. They  have to  remember days,  names,  songs  and

stories, so their memory is the whole time being exercised.

     So if you want to have a good memory, learn from the people: practise remembering things in a way

as other people do.

1. Someone can't have a good memory if ________.

A. he can't read or write

B. he doesn't use his memory often

C. his parents haven't a good memory

D. he doesn't use his arms or legs for some time

2. If you do not use your arms or legs for some time, ______.

A. you can't use them any more

B. they will become stronger

C. they become weak but they slowly become strong again

D. they become weak and won't become strong until you use them again

3. Which of the following is TRUE ?

A. Your memory  doesn't work in the same way as your arms or legs.

B. Your memory, like your arms or legs, becomes weak if you do not give it enough chance for practice.

C. Don't learn how to read and write if you want to have a better memory.

D. A good memory comes from less practice.

4. Few people know that it is only ______ if a friend has a poor memory.

A. his own fault

B. his parents' fault

C. his teachers' fault

D. his grandmother's fault

5. The writer of this passage wants to tell us ________.

A. how to use our arms or legs

B. how to read and write

C. how to have a good memory

D. how to learn from the people

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