什么是安全阀,作用是什么?

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问题:

什么是安全阀,作用是什么?

考点:制氢装置工程师焦炭塔焦炭塔题库
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已知f(x)=
x2(|x|≤1)
1 (|x|>1)

(1)求f(x)的定义域和值域;
(2)求f(
1
2
),f(-2),f(a2-1).
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从A、B、C、D四个选项中,选出与句子画线部分意义相同或相近并能替代的那一项。

1. —Jim, is your brother in?

    —No, he is reading in the library at the moment.

A. right away

B. at times

C. right now

D. at once

2. —Talking loudly in a library is impolite.

    —In fact, we should also take care not to cough or sneeze loudly in public.

A. look after

B. be careful

C. take care of

D. look up

3. —Mei will represent our class in the English Speech Contest.

   —She is clever and can speak English really well. She will not make us disappointed.

A. knock into us

B. care about us

C. let us down

D. help us out

4. —Li Na won the tennis championship in the French Open on June 4, 2011.

    —We take pride in her. She is the first Asian professional tennis player to win it.

A. are interested in

B. are terrified of

C. are proud of

D. are used to

5. —So where do you want to go, Tina?

    —Let's go to the Blue Lagoon. The soft music makes me relaxed.

A. exhausted and sleepy

B. calm and comfortable

C. active and energetic

D. tense and disgusted

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概念的内涵和外延之间()关系。

A.是一致的

B.是相反的

C.没有

D.是倒U形的

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在社会主义初级阶段,我国各族人民团结奋进的共同政治基础是 [ ]

A.“三个代表”重要思想

B.党的坚强领导 

C.四项基本原则

D.人民民主专政 

题型:问答题 简答题

遮阳板的基本形式有()、()、()和()几种。

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