问题 填空题

在日常生活中如取款、上网等都需要密码.有一种用“因式分解”法产生的密码,方便记忆.原理是:如对于多项式x4-y4,因式分解的结果是(x-y)(x+y)(x2+y2),若取x=9,y=9时,则各个因式的值是:(x-y)=0,(x+y)=18,(x2+y2)=162,于是就可以把“018162”作为一个六位数的密码.对于多项式4x3-xy2,取x=10,y=10时,用上述方法产生的密码是:______(写出一个即可).

答案

4x3-xy2=x(4x2-y2)=x(2x+y)(2x-y),

当x=10,y=10时,x=10;2x+y=30;2x-y=10,

用上述方法产生的密码是:101030或103010或301010.

阅读理解

Empathy(同情心) lets us feel another person’s pain and drives us to help. Do any other animals feel empathy? Scientists recently found that rats(老鼠) do, too.

Most people don’t like rats. In many people’s eyes, rats are only bad. But Jean Decety and his partners at the University of Chicago did an experiment. It showed that rats are kind, warm-hearted animals. They can feel each other’s pain.

Scientists placed pairs of rats in plastic cages(笼子) for two weeks. During this time they got to know each other. Then they put one of the rats from each pair into a small container(容器) in the cages. The small container had a door. It was so designed as to fall to the side when the free rat touched it. Many of the trapped(困住的) rats squeaked(吱吱叫) to show their discomfort. The other rats of the pairs could see their suffering(受苦的) friends clearly.

In most pairs, the free rats would become very worried about their friends. They kept trying to save their friends again and again throughout the month. Scientists put the rats’ favorite chocolate in the cages, but the rats didn’t eat it until they had saved their friends successfully. Scientists also found that female rats seemed to act more empathetic than male rats.

“The results are the first to show that rats take action in response to another’s trouble,” Decety said. “Monkeys and chimpanzees have similar behavior. But unlike those animals, rats can be ready used in laboratory studies. They will help us to learn which parts of the brain lead to empathy and helping behavior and whether empathy is natural.”

小题1:A person with empathy is often _____.

A.kind-hearted

B.clever

C.active

D.strong小题2:Why didn’t the free rats eat the chocolate at first?

A.Because they were not hungry at that time.

B.Because chocolate was not their favorite food.

C.Because they wanted to save the trapped rats first.

D.Because they were afraid that the chocolate was bad.小题3:Which of the following animals were NOT mentioned in the passage?

A.Monkeys.

B.Chimpanzees.

C.Rats.

D.Cats.小题4:What does the passage mainly tell us?

A.Rats can feel other animals’ pain.

B.Chocolate is rats’ favorite food.

C.Rats are empathetic and can feel each other’s pain.

D.Female rats are more empathetic than male rats.

多项选择题