问题 问答题 简答题

脱碳反应对炼钢过程有何重要意义?

答案

参考答案:

①铁液中的碳通过脱碳反应被氧化到接近或等于出钢时钢液中碳的规格范围内。

②对熔池的循环搅拌作用。

③生成的CO是去除钢中气体所必需的。

④有利于钢中非金属夹杂物的排除。

⑤为炼钢反应提供热源。

⑥有利于吹炼过程渣钢间反应。

单项选择题
阅读理解

阅读理解。

     One evening I went out and left my 17-year-old son and his girlfriend in charge of his 8-year-old

brother and 4-year-old sister. I left with complete confidence that the older children would do a

wonderful job of babysitting the younger children. Later, I discovered that I was completely wrong.

     I had decided to return home earlier than planned so that my son and his girlfriend could go out. I

called home with this happy news.But instead of hearing his cheerful, grateful voice on the other end

of the line, allI heard was the sound of a telephone ringing.

     It was, I should point out, after 10 p.m., when the two younger children should have been in bed,

and when the two older children should have been answering the phone. "I'll give him a lesson, " I said.

I decided they must be outside. Why they might be outside at 10:30 on a winter night I had no idea,

but it was the only explanation I could come up with.

     Finally, in desperation (绝望), I called his girlfriend's house. His girlfriend answered. "Yes," she said

brightly, "He's right here."

     He came on the phone.I was not my usual calm, patient.After all, one of the rules of survival for

modern parents is that you can't trust modern teenagers. "Where are the children?" I said. He said they

were with him. They had done nothing wrong. My son had taken the younger children over to his girlfriend's house just for ice cream and cake. Well, it turns out that I shouldn't have believed it. It was only part

of the truth.

      The following Saturday evening we were at my parents' home, celebrating my birthday. My oldest

son gave me the children's gifts-a series of lovely color photographs of my children, dressed in their best

clothes, and wearing their most wonderful expressions. They are pictures to treasure a lifetime, all taken

by the father of my son's girlfriend.

1. The author went out and left her eldest son in charge of the younger children because _____.

A. she knew that his girlfriend was a good baby-sitter

B. she believed he could take good care of the younger ones with the help of his girlfriend

C. the older children have always loved the younger ones

D. she could not find a baby-sitter on that winter night

2. Shortly after the author left home one evening, she discovered that _____.

A. her son had brought his girlfriend home    

B. her son had left home with his girlfriend

C. she shouldn't have completely trusted her son  

D. she should have taken the children along with her

3. "It was only part of the truth." implies that the children not only enjoyed ice-cream but also _____.

A. had their pictures taken

B. received some gifts

C. had a birthday party  

D. showed off their best clothes