电容器的最大功率指的是在什么情况下的功率?

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问题:

电容器的最大功率指的是在什么情况下的功率?

考点:铁路知识考试电气化铁道供电系统电气化铁道供电系统题库
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若m、n取正数,p、q取负数,则以下式中其值最大的是[ ]

A.m﹣(n+p﹣q)

B.m+(n﹣p﹣q)

C.m﹣(n﹣p+q)

D.m+(n﹣p+q)

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阅读理解

Dear Mom,

       Time flies quickly. Two months has gone by since I joined this boarding school. Everything is going

well. During my first month here, I was like a fish out of water. I came to realize how many things I should

thank you for.

       On the cold winter days, I have to get up early almost every morning to fetch hot water. I began to

feel ashamed that I never said 'thank you" every time you prepared (准备) hot water for me each morning on winter days before I got up.

       I am no longer that girl who was often unable to find her books in her bedroom. It used to take me a

lot of time to collect all the books for the day's classes. But I have gotten over that bad habit now. And

now I know how much time you used to take to collect my books every evening.

       I have learned to do the laundry on my own now. I came to realize that washing clothes is a boring

job, especially on winter days. Sometimes there is no hot water and I have to wash my clothes with cold

water by hand.

       I came to know how grateful (感激的) I should be to have you as my mom. Thank you, Mom.

                                                                                                                                                     Yours, 

                                                                                                                                                     Silvia

根据材料内容,选择最佳选项。

1. Silvia has been at the boarding school for _______.

A. one week        

B. two weeks

C. one month        

D. two months

2. The underlined word "ashamed" means "________" in Chinese.

A. 惭愧的

B. 恐惧的

C. 吃惊的

D. 轻率的

3. At the boarding school, Silvia doesn't ______ anymore.

A. do her laundry

B. put her books everywhere

C. say "thank you" to her mother

D. spend much time on her studies

4. From the letter we can learn that ______.

A. Silvia used to do her laundry at home

B. Silvia often helps her mom do housework  

C. Silvia's mom has done many things for her before

D. Silvia's mom usually does the laundry with cold water

5. Silvia wrote this letter in order to tell her mom _______.

A. her school life    

B. her thanks from her heart

C. she could do many things

D. she could look after herself  

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左旋多巴不良反应较多的原因是()

A.在脑内转变为去甲肾上腺素

B.在脑内形成大量多巴胺

C.对β受体有激动作用

D.在体内转变为多巴胺

E.对α受体有激动作用

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在六大营养物质中,能为生命活动提供能量的是          

题型:问答题 简答题

在热水管和蒸汽管道上,采用无缝钢管一般气压在( )MPa。

A.≤0.6

B.>1.3

C.>0.6

D.>2

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