试题与答案

求如图所示的交变电流的有效值,其中每个周期的后半周期的图象为半个周期的正弦曲线(

题型:选择题

题目:

求如图所示的交变电流的有效值,其中每个周期的后半周期的图象为半个周期的正弦曲线(   )

A.5A

B.5A

C.5/2A

D./2A

答案:

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题型:阅读理解

BEIJING---No Car Day was first started by 34 cities in France on September22, 1998. It was started to protect the environment. By now, more than 1,000 cities around the world have had a No Car Day.

The first No Car Day in China was in Chengdu in 2001. Other cities, including Taipei, Shanghai and Wuhan, also support( 支持) the day.

In Beijing, more and more people are joining in the activity. It asks drivers to leave their cars at home for one day each month and walk or ride a bike to work. It also calls on Beijingers not to use cars on June 5 ( World Environment Day ).The slogan for the day is, “ If we drive for one less day, we can have one more nice day.”

So far more than 200,000 drivers have shown their support “ We can’t control the weather, but we can choose not to drive,” said Wu Zonghua, a car club chairman. Beijing is trying to have 238 blue sky days this year. In the first quarter of this year, Beijing only had 52 blue sky days. This was 11 days less than the number for the same period last year. Much of the dust( 灰尘 ) comes from the desert(沙漠), but cars cause most of the air pollution.(污染). We must do more for No Car Day.

小题1:There are      cities in China that support No Car Day according to the passage.

A.three

B. four

C. five

D.six小题2:The activity of No Car Day encourages Beijing drivers        .

A.not to work on No Car Day

B.to enjoy having a day off

C.leave their cars at home for repair

D.to ride a bike or walk instead of driving to work小题3:We can know from the passage that       .

A.more and more people in Beijing are joining car clubs

B.people will have one more World Environment Day each month

C.more and more people won’t drive on No Car Day in Beijing

D.more people in the world won’t drive any more

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