问题 解答题

用一个平面截半径为25cm的球,截面面积是225πcm2,则球心到截面的距离为多少?

答案

 球心到截面的距离是20 cm

解:在如所示球中,因为截面的面积是225πcm2,所以截面的半径为15 cm.

所以 cm.所以球心到截面的距离是20 cm.

知识点:简单几何体和球

阅读理解

My mother was a housewife. She thought that successful people spent a lot more time reading than watching TV. So she asked my brother and me not to watch too much TV, but to read two books every week in our free time. She would check them with marks, though she couldn’t read the book at all.

When I went to high school, I was an A-student, but not for long. I wanted cool clothes and hung out with friends. I became a C-student, but I didn’t care. One night I complained about not having enough Italian shirts. Then my mother gave me all the money and said I could get the money left to buy shirts if I finished buying all the things the family needed. I was pleased with that, but after I bought those things, there was no money left. I got to know how difficult it was for my mother to do all these. I went back to my studies and became an A-student again. Finally, my dream came true and I became a doctor.

My story is really my mother’s story----a woman with little education greatly changed my life as a parent. So I believe there is no job more important than parenting.

小题1:What did the writer’s mother do?

A.A worker.

B.A housewife

C.A teacher

D.A writer小题2:Why did the mother ask her children to read books in their free time?

A.Because she thought successful people spent more time reading.

B.Because she thought books were interesting.

C.Because she wanted her children to be happy.

D.Because she wanted her children to be doctors.小题3:Which was NOT the reason for the writer’s falling behind(落后)?

A.He only cared about clothes and didn’t study.

B.He spent more time hanging out with friends than studying.

C.He didn’t care that he went from being an A-student to a C-student.

D.He spent much time reading storybooks.小题4:What was the writer’s dream?

A.To be a doctor.

B.To be a teacher.

C.To be an A-student

D.To find a good job.小题5:The writer mainly wants to tell us that ______.

A.mothers with little education change their children more.

B.his mother is cruel and unhelpful

C.there is a job more important than parenting.

D.his mother has an important influence(影响)on him.

单项选择题