频率一定的声源在空气中向着静止的接收器匀速运动。以u表示声源的速度,V表示声波的

题型:不定项选择

问题:

频率一定的声源在空气中向着静止的接收器匀速运动。以u表示声源的速度,V表示声波的速度(u<V),v表示接收器接收到的频率。若u增大,则[ ]

A.v增大,V增大

B.v增大,V不变

C.v不变,V增大

D.v减少,V不变

考点:多普勒效应
题型:不定项选择

下列各组词语中加点字的读音与所给注音全都相同的一组是( )

A.龟guī 龟卜 龟鉴 龟裂 龟板

B.供gōng 供养 提供 供销 供奉

C.给jǐ 补给 自足自给 给予 给养

D.冲chōng 冲锋 冲突 冲动 冲劲

题型:不定项选择

有价证券充抵保证金的金额不得高于()标准中的较低值。

A.有价证券基准计算价值的75%

B.有价证券基准计算价值的80%

C.会员在期货交易所专用结算账户中的实有货币资金的3倍

D.会员在期货交易所专用结算账户中的实有货币资金的4倍

题型:不定项选择

档案被称为“历史文明之母”,“文明之母”是因为档案具有()

A.信息加工功能

B.信息回溯功能

C.知识贮存与传播功能

D.查考备用功能

题型:不定项选择

One day when I was driving on the freeway, I noticed all the way there were large dividing walls, which had been built between it and the road running parallel to it, for noise reduction (减少) and a sense of separation. The purpose was to create a sense of privacy (隐私) for people on the other side.

This got me thinking: How often do we put up mental barriers that keep us distant from others? Lifting the artificial barriers that keep us apart can offer opportunities to express our goodwill and create better relationships. If we can do like this, maybe our life will be a little different.

There is a little post office in a nearby town, and since it is closer to me than the post office in my own town, I go there. One day, with many people jammed into the little building, a man came hurrying in to mail a letter, and the girl at the counter saw he had too little postage on it. She told him he needed 2 more cents. Obviously he was a little at a loss. He had hurried over from his office, and didn’t have any money on him or time to stand in line. He was going to run back to get the needed money and wait in line again, but he hurried to get the letter mailed in the first place.

As we were watching him, one woman volunteered a two-cent stamp, and the whole line became very quiet. It was a beautiful moment. The man hesitated for a little while and asked her if she was sure, and she assured him she was fine with giving him the stamp. He offered to go back to his office to get the two cents, and she told him not to bother.

It was a small thing, but it meant something to both of the people involved, and to the rest of us. We aren’t a yard that needs defining or a freeway that needs barriers. We are human beings who can contribute to each other’s wellbeing by taking time to pay attention and interact. After all, we are all parts of a whole living in society.

小题1:The purpose of the first paragraph is to __________.

A.summarize the main idea

B.give detailed information

C.tell readers the author’s opinion

D.introduce the topic小题2:What happened after the man being told he needed two more cents?

A.The man went back to his office immediately.

B.The man turned to a lady for help.

C.A woman offered a stamp to the man.

D.The man waited in line patiently.小题3:What can we learn about the author?

A.She pays too much attention to privacy.

B.She believes people should participate in the world around them.

C.She confuses real barriers with false ones.

D.She insists all small things always have the greatest meaning.小题4:Which of the following would be the best title for the passage?

A.Artificial Barriers

B.Unnecessary Separation

C.An Unforgettable Experience

D.The Kindness of People

题型:不定项选择

计算人口自然增长率的分母是

A.某年平均人口数
B.某年15~49岁妇女数
C.某年活产总数
D.某年结婚登记人数
E.某年孕妇数

更多题库