[单选题]在输电线路参数中属于耗能参数的是-我要搜题网

[单选题]公称通经DNs50的调节阀现场安装时、阀体中心线距地面或阀下端物体的最小距离是(　　)。
A.300mm
B.400mm
C.500mm

[不定项选择题]共用题干 Early or Later Day Care
The British psychoanalyst John Bowiby maintains that separation from the parents during the sensitive "attachment"period from birth to three may scar a child's personality and predispose to emotional problems in later life.Some people have drawn the conclusion from Bowlby's work that children should not be subjected to day care before the age of three because of the parental separation it entails,and many people do believe this.But there are also arguments against such a strong conclusion.
Firstly,anthropologists point out that the insulated love affair between children and parents found in modern societies does not usually exist in traditional societies.For example,in some tribal societies,such as the Ngoni,the father and mother of a child did not rear their infant alone-far from it.Secondly,common sense tells us that day care would not be so widespread today if parents,care-takers found children had problems with it.Statistical studies of this kind have not yet been carried out,and even if they were,the results would be certain to be complicated and controversial.Thirdly,in the last decade there have been a number of careful American studies of children in day care,and they have uniformly reported that day care had a neutral or slightly positive effect on children's development.But tests that have had to be used to measure this development are not widely enough accepted to settle the issue.
But Bowlby's analysis raises the possibility that early day care has delayed effects.The possibility that such care might lead to,say,more mental illness or crime 15 or 20 years later can only be explored by the use of statistics.Whatever the long-term effects,parents sometimes find the immediate effects difficult to deal with.Children under three are likely to protest at leaving their parents and show unhappiness.At the age of three or three and a half almost all children find the transition to nursery easy,and this is undoubtedly why more and more parents make use of child care at this time.The matter,then,is far from clear-cut, though experience and available evidence indicate that early care is reasonable for infants. Which of the following best expresses the writer's attitude towards early day care?
A.Children under three should stay with their parents.
B.Early day care has positive effects on children's development.
C.The issue is controversial and its settlement calls for the use of statistics.
D.The effects of early day care on children are exaggerated and parents should ignore the issue.

[单选题]在输电线路参数中属于耗能参数的是A.电抗、电阻B.电纳、电阻 C.电导、电抗D.电阻、电导

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[单选题]在输电线路参数中属于耗能参数的是
A.电抗、电阻
B.电纳、电阻
C.电导、电抗
D.电阻、电导