问题 单项选择题

根据《电子计算机机房设计规范(GB50174—1993》,计算机网络机房应选择采用4种接地方式。 (16) 接地系统是将电源的输出零电位端与地网连接在一起,使其成为稳定的零电位。要求该接地的地线与大地直接相通,其接地电阻要求小于1Ω。

A.交流工作

B.线槽

C.直流工作

D.防雷

答案

参考答案:C

解析:[要点解析] 机房主要采用下列4种接地方式。
①交流工作接地:该接地系统把交流电源的地线与电动机、发电机等交流电动设备的接地点连接在一起,然后再将它们与大地相连接。交流电接地电阻要求小于4Ω。
②安全工作接地:为了屏蔽外界的干扰、漏电及电火花等,所有计算机网络设备的机箱、机柜、机壳、面板等都需接地,该接地系统称为安全地。安全地接地电阻要求小于4Ω。
③直流工作接地:这种接地系统是将电源的输出零电位端与地网连接在一起,使其成为稳定的零电位。要求地线与大地直接相通,并具有很小的接地电阻。直流电接地电阻要求小于1Ω。
上述3种接地都必须单独与大地连接,互相的间距不能小于15m。地线也不要与其他电力系统的传输线绕在一起并行走线,以防电力线上的电磁信号干扰地线。
④防雷接地:执行国家标准《建筑防雷设计规范》。

问答题
阅读理解

You have the ability to decide whether you are happy or not. Happiness is a choice.

You can’t depend on someone else to make you happy. That is a lesson I learned early in my marriage. I realized that I couldn’t rely on my husband as my source of happiness. I learned that my happiness depended on myself and not my husband’s actions. I learned that you have to choose to be happy.

You can choose your emotions. True happiness comes from within, and it can’t be forced by outside force. So how do you choose happiness? The same way, you choose to smile or choose to wear a certain outfit(一套衣服). You choose it because that’s what you want to experience in you life.

You want to buy a new pair of shoes so you choose a pair that you like and feels good. You wouldn’t buy a pair of shoes that you don’t like or that doesn’t fit well, right? So why do we keep choosing emotions and feelings that don’t make us feel good?

Choosing to be happy after you realize your anger has shown up (or even choosing to be calm) can be beneficial. We choose our feelings; no one else can do that for us. If we let others get to us, influence our emotions — we are giving them power over us. When others cause us anger or pain, we are giving them our power.

We need to keep our feelings in check and not to react(反应) automatically to what is thrown at us. We need to think our actions out instead of just reacting to what someone says or does.

Remember that we can always choose happiness. At first it will be difficult to just switch(使转变)your thoughts and feelings from anger, self-doubt, or fear to joy and happiness. But it is only a thought away. Don’t dwell on(细想) what happens to you unnecessarily but realize what is causing you to feel that way. Realize that thoughts, feelings and emotions can change. Then move on and choose to be happy.

64. What’s the best title of this passage?

A. Pretend to Be Happy

B. Choose Your Emotions

C. Choose to Be Happy

D. Find Happiness

65. The lesson the writer learned in her marriage is          .

A. one can’t depend on someone else to make himself or herself happy

B. balancing the relationship between husband and wife is an art

C. she can depend on her husband to find happiness

D. happiness can be influenced by outside force

66. Why did the writer mention buying shoes?

A. To offer advice on how to choose comfortable shoes.

B. To use it as an example to illustrate(阐述)her point of view.

C. To compare choosing shoes and choosing an outfit.

D. To help move to the next paragraph easily.

67. The writer suggests that we should          .

A. let others control our feelings

B. respond immediately to others’ words

C. hold back our feelings properly

D. pay more attention to words than actions