问题 问答题 简答题

管道的公称压力是什么?

答案

参考答案:

公称压力是由国家标准规定用来表示管道的压力等级范围,也是用来选用管道和进行计算的。

管道所承受的工作压力会随着管道的材料和管内介质温度的不同而变化。同一材料的管道的最大允许工作压力是随着介质温度的升高而降低的。

阅读理解

阅读理解。

     I always felt sorry for the people in wheelchair. Some people, old and weak, can not get around by

themselves. Others seem perfectly healthy, dressed in business suits. But whenever I saw someone in

a wheelchair, I only saw a disability, not a person.

     Then I fainted at Euro Disney due to low blood pressure. This was the first time I had ever fainted,

and my parents said that I must rest for a while after First aid. I agreed to take it easy but, as I stepped

towards the door, I saw my dad pushing a wheelchair in my direction! Feeling the color burn my cheeks,

I asked him to wheel that thing right back to where he found it.

     I could not believe this was happening to me. Wheelchairs were fine for other people but not for me,

as my father wheeled me out into the main street, people immediately began to treat me differently.

     Little kids ran in front of me, forcing my father to stop the wheelchair suddenly. Bitterness set in as 

I was thrown back and forth. "Stupid kids-they have perfectly good legs. Why can't they watch where

they are going?" I thought. People stared down at me,with pity in their eyes. Then they would look away,

maybe because they thought the sooner they forgot me, the better.

     "I am just like you!" I wanted to scream. "The only difference is you've got legs, and I have wheels."

     People in wheelchairs are not stupid. They see every look and hear each word. Looking out at the faces,

I finally understood: I was once just like them. I treated people in wheelchairs exactly the way they did not

want to be treated. I realized it is some of us with two healthy legs who are truly disabled.

1. When the writer was healthy, she once _____.

A. showed respect for disabled people

B. imagined herself sitting in a wheelchair

C. looked down upon disabled people

D. saw some healthy people moving around in wheelchairs

2. Facing the wheelchair for the first time, the writer _____.

A. refused to accept it immediately

B. felt curious about it

C. thought it was ready for her father

D. got ready to move around in it immediately

3. The writer wants to say _____ from her own experience.

A. life is so changeable that nobody can foresee

B. people with healthy legs are truly disabled

C. people often eat their bitter fruit

D. life is the best teacher for people

4. Which is the best title for the passage?

A. The Wheelchairs Are as Good as Two Legs

B. People with Two Legs Are Truly Healthy

C. How to Get Used to Wheelchairs

D. The Difference between Healthy People and the Disabled

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