问题 不定项选择

如图所示,用水平力F推乙物块,使甲、乙、丙三个完全相同的物块一起沿水平地面以相同的速度做匀速直线运动,各物块受到摩擦力的情况是

[ ]

A.甲物块受到一个摩擦力的作用

B.乙物块受到两个摩擦力的作用

C.丙物块受到两个摩擦力的作用

D.甲物块与乙物块受相同大小的摩擦力

答案

答案:C

阅读理解

Here in Alaska, the wolf almost disappeared a few years ago, because hunters were killing hundreds of them for sport. However, laws were passed to protect the wolves from sportsmen and people who catch the animals for their fur. So the wolf population has greatly increased. Now there are so many wolves that they are destroying their own food supply.

A wolf naturally lives on animals in the deer family. People there also hunt deer for food. Many of the animals have been destroyed by the very cold winters recently and by changes in the plant life there. When the deer can’t find enough food, they die.

If the wolves continue to kill large numbers of deer, the deer will disappear some day. And the wolves will, too. So we must change the life cycles there. If we killed more wolves, we would save them from starving. We also save deer and some farm animals.

In another northern state, wolves attack cows and chickens for food. Farmers want the United States government to send a team of scientists to study the problem. They believe it is necessary to kill wolves in some areas and to protect them in places where there is a small population.

小题1:In Alaska, laws have been passed to ____.

A.protect people from wolves and deer

B.protect wolves from becoming dangerous

C.protect wolves from dying out

D.keep wolves from killing large numbers of deer小题2:Why is it that if wolves go on killing a good many deer the wolves will die out?

A.Because wolves will have no deer to kill.

B.Because people will kill them for punishment.

C.Because killing deer is dangerous.

D.Because wolves mainly live on deer.小题3:In order to protect more deer from being killed, one way is to ____.

A.pass a law

B.keep deer away from wolves

C.kill more wolves

D.serve wolves more food小题4:Which of the following statements is true according to the passage?

A.Some wolves in some areas must be killed, which others should be protected.

B.Wolves should be protected, for there’s a small population of it on earth.

C.All wolves should be protected, for they eat deer, cows and chicken.

D.It is necessary for scientists to protect wolves, or the cycle of life will be changed

单项选择题 B型题