问题 选择题

下列说法中正确的是(  )

A.所谓参考系就是相对地面静止不动的物体

B.在研究贝克汉姆“香蕉球”的旋转效应时,可以把球看作质点

C.在研究火车过一座短桥的时间时,不能把火车看作质点

D.一个运动过程可能出现路程等于零,而位移不等于零

答案

A、参考系是在描述物体的运动时,被选定做为参考、假定为不动的其他物体.被选为参考系的物体可以是静止的也可以是运动的,故A错误;

B、做“香蕉球”的旋转效应时,要观察球的旋转等,球的大小此时不能忽略,不能把球看作质点.故B错误;

C、火车过桥时,火车长度和桥的长度相比不能忽略,因此研究火车通过一座铁路桥所用的时间时,火车不能看作质点,故C正确;

D、一个运动从初位置出发又回到原位置,则位移为零,但只要有运动,则路程就不能为零,故D错误;

故选C.

阅读理解

Having put down your pens at the end of the college entrance exam, you have ended 12 years of hard study. Forget your studies for a while. It’s time to enjoy yourselves!

There are many ways to celebrate this special month of graduation. You can have photos taken with your classmates and teachers, or dine out together and exchange gifts.

High school students in Western countries such as the United States and Canada usually have a prom to mark their graduation. It’s to mark the time kids turn into young men and women. After the prom, teenagers either go to college or find a job. It means they are no longer as dependent on their parents as they were before.

At the prom, boys usually dress in dinner jackets and bow ties, though many different types of formal clothes are worn. Traditionally, girls give boys matching boutonnieres ( 佩带在扣眼上的花). Girls traditionally wear formal dresses, or dress to shock or be noticed, in shiny or brightly colored materials.

Common prom activities include dining, dancing, the crowning (加冠) of a prom king and queen, and just talking to friends.  In some cases, high school students collect funds for their class prom through the four years of their high school.

High schools in or near large cities may rent ballrooms at expensive hotels or, to be unusual, in a pleasure cruise boat.

But often costs are cut by simply using the school gym. Students make a lot of effort to decorate the gym to make the event special. The music played at the prom will be the most popular kinds, like rock and hip-hop.

The students elect the Prom Queen. She is partnered with a Prom King who is elected similarly. These are great honors that the pair take very seriously. The two dance with each other to celebrate their election.

小题1:The word "prom" is probably closest in meaning with________.

A.a party to celebrate graduation

B.a dancing competition

C.a fashion show

D.an election ceremony小题2:Which of the following is an economical way to hold the prom?

A.Renting a ballroom.

B.Taking a cruise boat.

C.Holding it in the school gym.

D.Wearing informal dresses.小题3: What clearly indicates that prom is very important to students?

A.Music is played at the prom.

B.They take pictures at the prom.

C.The King and Queen dance with each other.

D.They wear formal clothes or special clothes.小题4:For what do the students just talk to friends at a prom?

A.They don’t want to get help from their parents.

B.They will part with their friends in a short time.

C.They don’t like to be accompanied by their parents.

D.They want to be elected by their friends as the Prom King or Queen.小题5:How is the prom significant to the students?

A.They can be relieved from the study pressure.

B.They are going to say goodbye to their friends.

C.They have chances to be elected as the Prom King or Queen.

D.The prom marks the graduation and after it they will be independent.

单项选择题 共用题干题