问题 问答题

什么叫石墨化其影响因素有哪些

答案

参考答案:铸铁中的碳从铁液中直接析出或由渗碳体分解出石墨的过程,统称石墨化。影响石墨化的因素是铸铁的化学成分(即碳、硅、锰、硫、磷等的含量)和铸铁浇注后的冷却速度这两个因素。

阅读理解

Feeling left out?

A reader wrote in to say that she was feeling lonely at break because her best friend wasn’t around.Here’s our advice to her—and to all kids who feel lonely sometimes. It’s hard when a best friend isn’t around—maybe because she moved to a different school or a different class.You may feel lonely at break or lunchtime.You want to have new friends.But how do you make them? Maybe it seems like everybody else already has their friends.But remember, there’s always room for more friends.

Start by looking around your classroom—think about which kids you’d like to play with at break.Look for chances to say hi to them,smile,and be friendly.Offer to share something or express your appreciation(欣赏)to them.Invite someone to play with you or say “Do you want to sit here?” in the lunchroom.When you’re at break,walk over to kids you want to play with.Act friendly,and say “Hi,can I play, too?” or just join in.

If you have trouble doing this or if you’re feeling shy, ask your teacher to help you make  new friends.Teachers are usually pretty good at matching up friends.The best way to make friends is to be a friend.Be kind,be friendly,share,say nice things,offer to help—and pretty soon,you’ ll have one,or two,or even more new friends. You might still miss that special best friend.But when you see each other, you can share something you didn’t have before she left:You can introduce her to your new friends!

小题1:This text is written for ________ .

A.teachers

B.parents

C.students

D.visitors小题2:According to the writer, some kids feel lonely at break because they  ________  .

A.have trouble with their studies

B.don’t have their best friends around

C.need their parents to be with them

D.are too young to look after themselves小题3:The underlined words in Paragraph 4 refers to ________  .

A.sharing your ideas

B.talking before many people

C.studying better at school

D.developing new friendship小题4:Some kids need help from teachers to make friends because  ________   .

A.they miss their old friends a lot

B.they have no time to stay with others

C.teachers know who wants a new friend

D.they are shy or not good at making friends小题5:The expression “feeling left out'’ means“ _______    ” in Chinese.

A.受冷落    8.被调侃    C.挨批评    D.遭攻击

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