问题 不定项选择

骑自行车的人从静止开始沿直线运动,他在第1s内、第2s内、第3s内、第4s内通过的距离分别为1m、2m、3m、4m。关于这个人的运动,下列说法正确的是[ ]

A.4s末的瞬时速度为2.5m/s

B.4s末的瞬时速度为4.0m/s

C.前4s内的平均速度为2.5m/s

D.前4s内的平均速度为4.0m/s

答案

答案:C

阅读理解

阅读理解。

      David did well in his other subjects except physics. Mr. Brown, his physics teacher, gave him his

physics paper and said to him, "Show it to your dad and ask him to sign his name On the paper." 

      David played football until it was 7 o'clock. When he got home,his parents finished supper. His dad

was watching TV and his mom was doing the dishes in the kitchen as usual. 

     "Dad, may I ask you some questions?" David asked happily. "Yes,of course," said his dad. "If you

can't answer them, you'll have to do something for me." "OK, I'll do as you tell me." said his dad. "What

is cooler, walking or sitting in the sun?" "Walking is cooler. It can make wind." "Which clothes can keep

out the sunlight, shirts or coats?" "Coats can keep out the sunlight because they are much thicker than

shirts." 

     "Is a man smart if he wears a coat and walks in the sun in summer?" David looked at his dad and

waited for his answer. His dad thought for a minute and shook his head. 

      David took out his paper, "Now sign your name on my paper, please."

根据短文内容,回答下列问题。

1.What does Mr. Brown teach at school?

      __________________________________________

2.Who usually washes the dishes at David's house?

      __________________________________________

3.Was David's father watching TV when he got home?

      __________________________________________

4.What do you think David's father has to do finally?

      __________________________________________

5.What do you think of David?

      __________________________________________

单项选择题