问题 选择题

如图所示电路中.A、B两灯均正常发光,R为一滑动变阻器,P为滑动片,若将滑动片向下滑动,则(        )

A.A灯变亮

B.B灯变亮

C.R1上消耗功率变大

D.总电流变大

答案

CD

题目分析:动片向下滑动,电阻变小,总电流变大,D正确。内电压变大,路端电压变小,A灯变暗。A错。流过A的电流变小,总电流变大,流过电流变大, ,上消耗功率变大。C对。电压变大,B灯与R两端电压变小,B灯变暗,B错。

点评:做在此类型的题目时,需要从部分电路的变化推出整体电路的变化,在推出另外部分电路的变化

阅读理解

阅读理解。

    China is the first developing country to host the Olympic Games in modern Olympic

history. It hopes to learn from other countries that have held Olympic Games. As well as

new buildings, the government (政府) wants more people to work in all the services (服务)

in Beijing. There are a lot more people in the city, because of all the visitors to the

Olympics. The city also need more places to eat and drink, because visitors eat out a lot. 

    The government says the Beijing Olympics are "green", "hi-tech" (科技), and "the

People's Olympics". They want everyone to feel part of the Olympics. So the Chinese people

have prepared for the Olympics too. Many people learn English to work as guides in 2008.

    The Beijing organizers (组织者) make sure everything that is built for the Olympics

can be used after the Games are over. So the Chinese people work for the Olympics and they

can benefit (受益) from the Olympics too. When the Olympics are over, the people of Beijing

can use the swimming pools and other Olympics sports centers.

1. China is _____ country to host the Olympic Games in modern Olympic history. [ ]

A. first

B. the first developing

C. the first Asian

D. the second

2. Why does the government want more people to work in Beijing? [ ]

A. Because the services in Beijing used to be very poor.

B. Because many people can't find jobs in their hometown.

C. Because many visitors will come to Beijing.

D. Because there are too many buildings

3. The new buildings for the Olympic can _____. [ ]

A. be used by the people after the Olympic Games

B. be closed after the Olympic Games

C. be only reopened when the next Olympic Games come

D. be destroyed (破坏)

4. What does "the People's Olympics" mean? [ ]

A. It means that everyone in China will be a player in the Olympic Games.

B. It means that everyone in China feels part of the Olympics.

C. It means that all the Chinese people are rich enough to go to Beijing and watch 

   the Olympic Games.

D. It means that the Chinese people can make money.

5. What does this passage want to tell us? [ ]

A. The people in Beijing enjoy learning English.

B. The new buildings for the Olympics are very modern.

C. Everyone in China is great.

D. Everyone in China should do something for the Olympics and can also get a lot

   from the Olympics.

判断题