问题 问答题 简答题

低压配电系统中的中性线(N线)、保护线(PE线)和保护中性线(PEN线)各有哪些功能?

答案

参考答案:

中性线(N线)的功能:一是用来接驳相电压220V的单相用电设备二电是用来传导三相系统中的不平衡电流和单相电流三是减小负载中性点的电位偏移。

保护线(PE线)的功能:它是用来保障人身安全、防止发生触电事故用的接地线。

保护中性线(PEN线)的功能:它兼有中性线(N线)和保护线(PE线)的功能。这种保护中性线在我国通称为“零线”,俗称“地线”。

阅读理解与欣赏

阅读课文中的语段,回答问题。

  皮鞋匠静静地听着。他好像面对着大海,月亮正从水天相接的地方升起来。微波粼粼的海面上,霎时间洒满了银光。月亮越升越高,穿过一缕一缕轻纱似的微云。忽然,海面上刮起了大风,卷起了巨浪。被月光照得雪亮的浪花,一个连一个朝着岸边涌过来……皮鞋匠看看妹妹,月光正照在她那恬静的脸上,照着她睁得大大的眼睛。她仿佛也看到了,看到了她从来没有看到过的景象,月光照耀下的波涛汹涌的大海。

1.下面的句子应该用怎样的语气读?把序号填在括号内。

A.遗憾,内疚  B.迫切  C.诚恳  D.体谅,安慰

(1)要是能听一听贝多芬自己是怎样弹的,那有多好啊!(  )

(2)是啊,可是音乐会的入场券太贵了,咱们又太穷。(  )

(3)哥哥,你别难过,我不过随便说说罢了。(  )

(4)不,我是来弹一首曲子给这位姑娘听的。(  )

2.听着贝多芬的琴声,皮鞋匠想到了什么?用“_____”在文中画出来,并回答问题。

  皮鞋匠看到的第一幅画面是月亮刚______________,海面上______________,此时的音乐轻幽、舒缓;第二幅画面是月亮______________,天空中出现了______________,此时的音乐气势逐渐增强,曲调出现了波折;第三幅画面是海面上______________,______________,______________,此时的音乐高昂、激越,节奏越来越快。

单项选择题

It is incongruous that the number of British institutions offering MBA courses should have grown by 254 percent during a period when the economy has been sliding into deeper recession. Optimists, or those given to speed, assumptions, might think it marvelous to have such a resource of business school graduates ready for the recovery. Unfortunately, there is now much doubt about the value of the degree not least among MBA graduates themselves, suffering as they are from the effects of recession and facing the prospect of shrinking management structures.

What was taken some years ago as a ticket of certain admission to success is now being exposed to the scrutiny of cost-conscious employers who seek "can-dos" rather than "might-dos", and who feel that academia bas not been sufficiently appreciative of the needs of industry or of the employers’ possible contribution.

It is curious, given the name of the degree, that there should be no league table for UK business schools; no unanimity about what the degree should encompass; and no agreed system of accreditation. Su rely there is something wrong. One wonders where all the tutors for this massive infusion of business expertise came from and why all this mushrooming took place.

Perhaps companies that made large investments would have been wiser to invest in already existing managers, perched anxiously on their own internal ladders The Institute of Management’s 1992 survey, which revealed that eighty-one per cent of managers thought they personally would be more effective if they received more training, suggests that this might be the case. There is, too, the fact that training alone does not make successful managers. They need the inherent qualifications. Of character; a degree of self-subjugation; and above all, the ability to communicate and lead; more so now, when empowerment is a buzzword that is at least generating genuflexions, if not total conviction.

One can easily think of people, some comparatively unlettered, who are not lauded captains of industry. We may, therefore, not need to be too concerned about the fall in applications for business school places, or even the doubt about MBAs. The proliferation and subsequent questioning may have been an inevitable evolution. If the Management Charter Initiative, now exploring the introduction of a senior management qualification, is successful, there will be a powerful corrective.

We believe now that management is all about change. One hopes there will be some of that in relationship between management and science within industry, currently causing concern and which is overdue for attention. No-one doubts that we need more scientists and innovation to give us an edge in an increasingly competitive world. If scientists feel themselves undervalued and under-used, working in industrial ghettos, that is not a promising augury for the future. It seems we have to resolve these misapprehensions between science and. industry. Above all, we have to make sure that management is not itself smug about its status and that it does not issue mission statements about communication without realizing that the essence of it is a dialogue. More empowerment is required and we should strive to achieve it.

According to the passage, employers()

A. feel that they have not been consulted sufficiently about their needs

B. consider that cost-consciousness is the most important qualification

C. are more concerned about the value of the degree than graduates themselves

D. feel that MBAs will not be necessary because of shrinking management structures