问题 填空题

(文) 已知全集U={1,2,3,4,5},集合A={a1,a2,a3},则满足a3≥a2+1≥a1+2的集合A的个数是______.(用数字作答)

答案

当a3取5时,a2取4时,

a1就有3种取法;

a2取3时,a1就有2种取法..

a2取2时,a1就有1种取法

∴有1+2+3=6种结果,

一直做下去

当a3取4时,有1+2=3种结果,

当a3取3时,有1种结果,

根据分类计数原理把上面的取法加起来得到1+3+6=10种结果,

故答案为:10

阅读理解

阅读理解

     If I left the decisions up to my daughter, she'd never play competitive sports. In her first season of 

forced sports, when she was four years old, she cried every time she kicked the soccer ball. She stopped on the way from the parking lot to the soccer field, wailing that her legs hurt. And worse, she cried, "I'm

sweating!"

     A few years have passed, and she just completed her fourth soccer season. She's starting her second

year of softball. Sports trophies (奖杯) line her window platform.

     I learned from the years of football, soccer and baseball in my son's youth that kids need to experience being on a team, and they might not beg you to sign them up. You might have to force it on them.

     They need to learn about sacrificing, and about commitment. If you read parenting articles out there,

you'll find plenty of folks who shy away from competitive sports because they want their kid to always feel like a winner. I don't know what kind of idyllic (田园的) life these parents must be leading, but in my

world, I'm thinking I need to sign my kids up for something that will teach them about life's devastating

disappointments.

     Hence, I think my daughter picked up some good life lessons when her team lost almost every game in the last season. Sometimes life is like that. Sometimes you get a bad call, the people on your team suck, you're tired and don't feel like playing, the coach is mean to you, someone scratches your face and steals the ball. And the next week, you put on your uniform, and try your best.

1. What attitude does the author have towards competitive sports?

A. He supports children in taking part in competitive sports.

B. He doesn't like competitive sports himself.

C. He doubts whether competitive sports can really benefit children.

D. He believes competitive sports are not suitable for young children.

2. What do we know about the author's daughter?

A. She hates the author signing her up for competitive sports.

B. She hasn't realized the importance of competitive sports.

C. She wants to give up competitive sports.    

D. She now likes competitive sports.

3. What should we do if a child doesn't like competitive sports, according to the author?

A. Get him interested in sports first.

B. Sign him up for competitive sports.

C. Leave him alone.

D. Give him some trophies first.

4. In what way is life similar to sports?

A. They both mean a lot to children.

B. They both need great courage.

C. They are both full of hard times.

D. They both can teach children good lessons.

5. We can infer from the fourth paragraph that competitive sports       .

A. can destroy a child's feeling of success

B. are sometimes too cruel to children

C. have already been accepted by most parents

D. can prepare kids for the realities of life

单项选择题