搜题请搜索小程序“爱下问搜题”
问题 单项选择题

自耦变压器中性点必须接地，这是为了避免高压电网内发生单相接地故障时（）。

A、中压侧出现过电压

B、高压侧出现过电压

C、低压侧出现过电压

D、中性点出现过电压

答案

参考答案：A

单项选择题

Modern industrial society grants little status to old people. In fact, such a society has a system of built-in obsolescence. There is no formal system for continuing our education throughout our life in order to keep up with rapidly changing knowledge. When our education and job skills have grown obsolete, we are treated exactly like those who have never gained an education or job skills and are not encouraged or given the opportunity to begin anew.
As a society becomes more highly developed, the overall status of older people diminishes. Improved health technology creates a large pool of old people, who compete for jobs with the young. However, economic technology lowers the demand for workers and creates new jobs for which the skills of the aged are obsolete, forcing older people into retirement. At the same time, young people are being educated in the new technology and are keeping pace with rapid changes in knowledge. Finally, urbanization creates age-segregated neighborhoods. Because the old live on fixed incomes, they must often live in inferior housing. All these factors—retirement, obsolete knowledge and skills, inferior standards of living—lower the status of the aged in society.
A century ago, when one could expect to live only to 50 or so, the life span more or less coincided with the occupation and family cycle. But today the average life span allows for fifteen to twenty years of life after these cycles. It appears that our life span is outpacing our usefulness in society.

The high development of economic technology ______.

A．makes job skills out of fashion

B．lowers the demand for workers

C．forces old people into retirement

D．creates new jobs for older people
查看答案
单项选择题

近程导弹的射程为（）

A、小于500米

B、小于800米

C、小于1000米

D、小于1200米
查看答案