问题 选择题

安全教育已越来越引起学校和社会各界的高度重视,并开展了一系列丰富多彩的教育活动.某中学在一次关于家庭用电的“对”、“错”抢答比赛中,提出以下说法,其中应回答“对”的是(  )

A.如果发生了触电事故.要立即切断电源

B.若没有保险丝,可用细钢丝代替

C.控制家用电器的开关应该安装在零线上

D.电饭锅用三脚插头和三孔插座,是为了利用三角形的稳定性和美观性

答案

A、如果发生了触电事故.要立即切断电源,使接触者尽快脱离电源,故A正确;

B、当电路中有过大电流通过时,保险丝发热自动熔断,切断电路,从而起到保护电路的作用,如果用铜丝代替,因铜丝的熔点高,就起不到保护电路的作用,故B错;

C、如果开关接在零线和灯泡之间,火线直接接在灯泡时,虽然断开开关,但是火线和灯泡相连,触及灯泡会发生触电事故,故C错;

D、电饭锅用三脚插头和三孔插座,是由于这些用电器的外壳是金属,金属是导体,当用电器漏电时,会使金属外壳带电,若接上地线,电流就通过地线,流入大地,而防止了触电事故的发生,故D错.

故选A.

单项选择题 A1型题
阅读理解

     I'm usually fairly skeptical about any research that concludes that people are either happier or

unhappier or more or less certain of themselves than they were 50 years ago. While any of these

statements might be true, they are practically impossible to prove scientifically. Still, I was struck by

a report which concluded that today's children are significantly more anxious than children in the

1950s. In fact, the analysis showed, normal children aged 9 to 17 exhibit a higher level of anxiety today

than children who were treated for mental illness 50 years ago.

     Why are America's kids so stressed? The report cites two main causes: increasing physical isolation

(隔离) brought on by high divorce rates and less involvement in community, among other things and a

growing perception that the world is a more dangerous place.

     Considering that we_can't_turn_the_clock_back,_adults can still do plenty to help the next

generation.

     At the top of the list is nurturing(培育) a better appreciation of the limits of individualism. No child is

an island.  Strengthening social ties helps build communities and protect individuals against stress.

     To help kids build stronger connections with others, you can pull the plug on TVs and computers. 

Your family will thank you later. They will have more time for facetoface relationships, and they will get

more sleep.

     Limit the amount of virtual(虚拟的) violence your children are exposed to. It's not just video games

and movies; children see a lot of murder and crime on the local news.

Keep your expectations for your children reasonable. Many highly successful people never attended

Harvard or Yale.

     Make exercise part of your daily routine. It will help you cope with your own anxieties and provide

a good model for your kids. Sometimes anxiety is unavoidable. But it doesn't have to ruin your life.

1. According to the analysis, compared with normal children today, children treated as mentally ill 50 years ago ________.

A. probably suffered less from anxiety

B. were considered less individualistic

C. were less isolated physically

D. were probably less selfcentered

2. What does the author mean by saying "we can't turn the clock back" in the third paragraph?

A. It's impossible to forget the past.  

B. The social reality children are facing cannot be forgotten.

C. It's impossible to slow down the pace of change.

D. Lessons learned from the past should not be forgotten.

3. The author thinks that the conclusions of any research about people's state of mind are ________.

A. illogical  

B. confusing

C. surprising  

D. questionable