问题 选择题

姚明已成为美国NBA一流中峰,给中国人争得了很多的荣誉,让更多的中国人爱上了篮球这项运动.姚明某次投篮跳起可分为下蹲、蹬地(加速上升)、离地上升、下落四个过程,下列关于开始下蹲和下落两个过程的说法正确的是(忽略空气阻力)(  )

A.两过程中姚明都处于超重状态

B.两过程中姚明都处于失重状态

C.前过程为超重,后过程为完全失重

D.前过程为完全失重,后过程为超重

答案

姚明在下蹬的过程中,加速度方向向下,所以此时,人处于失重状态;当离开地面后,人对地面就没有作用力了,处于完全失重状态,此时有向下的加速度,加速度的大小为重力加速度g,所以B正确.

故选B.

阅读理解

阅读理解

     So you're between the ages of 13 and 24. What makes you happy?

    A worried, weary parent might imagine the answer to sound something like this: Sex, drugs, a little

rock 'n' roll (摇滚乐). Maybe some cash, or at least the car keys.

    It turns out the real answer is quite different. Spending time with family is the top answer to that

open-ended question, according to an extensive survey-more than 100 questions asked of 1,280

people ages 13-24 - conducted by The Associated Press and MTV on the nature of happiness

among America's young people.

    Next is spending time with friends, followed by time with a significant other. And even better for

parents: Nearly three quarters of young people say their relationship with their parents makes them

happy.

   "They're my foundation," says Kristiana St.John, 17, a high-school student from Queens in New

York. "My mom tells me that even if I do something stupid, she's still going to love me no matter what.

Just knowing that makes me feel very happy and blessed."

    You might think money would be clearly tied to a general sense of happiness. But almost no one

says "money" when asked what makes them happy, though people with the highest family incomes are

generally happier with life. However, having highly educated parents is a stronger predictor of happiness

than income.

    From the body to the soul: Close to half say religion and spirituality are very important. And more

than half say they believe there is a higher power that has an influence over things that make them happy.

Beyond religion, simply belonging to an organized religious group makes people happier.

     And parents, here's some more for you: Most young people in school say it makes them happy.

Overwhelmingly (压倒性地), young people think marriage would make them happy and want to be

married some day. Most also want to have kids.

     Finally, when asked to name their heroes, nearly half of respondents mentioned one or both of their

parents. The winner, by a nose: Mom.

1. In America, it is essential that young people should____..

A. make some money

B. enjoy rock'n'roll

C. stay with parents

D. have their own cars

2.  What Kristiana St.John says shows that____.

A. her mother is clever as other mothers

B. her mother loves her unconditionally

C. she is stupid and often does foolish things

D. she takes it a happy thing to cheat her mother

3. To a general sense of happiness, the survey indicates____.

A. money is the most concerned.

B. work condition is the key factor.

C. parents' quality is vital.

D. friends' quality is decisive.

4. From the 7th paragraph we can infer that____. 

A. the body is more important than the soul.

B. spirituality is more important than money.

C. religion is accepted by a large number of Americans.

D. religion group have saved many young Americans.

单项选择题