问题 选择题
如图所示,直线A为电源a的路端电压与电流的关系图象;直线B为电源b的路端电压与电流的关系图象;直线C为一个电阻R的两端电压与电流关系的图象.将这个电阻R分别接到a、b两电源上,那么(  )

A.R接到a电源上,电源的效率较高

B.R接到b电源上,电源的输出功率较大

C.R接到a电源上,电源的输出功率较大,但电源效率较低

D.R接到b电源上,电源的输出功率和效率都较高

答案

答案:C

阅读理解

Can you make animals work for us? Some scientists think that one day we can teach animals to do a lot of things for people. In a film shown on TV, you may see elephants, monkeys, tigers or some other animals are always given a little food to eat after they have done something. Scientists say that people can teach many different animals to do some of the easy work if they know they will get something to eat. We all know elephants can carry large logs(圆木),and dogs can look after houses. And we even teach animals to work in factories. In America, for example, people have used apes to help make cars and scientists think that those large monkeys may drive trains one day. Now people are trying to get them to do the same thing that man does.

小题1:Scientists think animals can help people to do something _____ .

A.if they know they will get food after doing something.

B.because animals are so clever.

C.if they know the work is easy enough

D.because most animals are friendly to man小题2:_______ can do some heavy work because they are so strong.

A.Tigers

B.Elephants

C.Monkeys

D.Dogs小题3:What does the underlined word “apes”   mean in Chinese?

A.猎豹

B.猿猴

C.孔雀

D.狮子小题4:Scientists are planning to make big monkeys to________.

A.make trains

B.carry logs

C.drive trains

D.work at school小题5:If we teach animals carefully, ________.

A.some animals can do the same things as man does.

B.all the animals can work for us.

C.many animals can do all the work as we do.

D.we may get many animals to work without giving them food.

问答题