当机械波在媒质中传播时，一媒质质元的最大变形量发生在（）。

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问题单项选择题

A．媒质质元离开其平衡位置最大位移处

B．媒质质元离开其平衡位置

C．媒质质元在其平衡位置处

D．媒质质元离开其平衡位置A/2处

答案

参考答案：C

阅读理解

阅读理解。

      Every year in English-speaking countries, people list the most popular names. Here are some examples.
In the United States at the moment the three most popular names for girls are Emily, Emma and Madison.
For boys, they are Michael, Joshua and Mathew. In Britain a parent today might call their little girl Grace,
Jessica or Ruby. If they have a little boy they could call him Jack, Thomas or Oliver. 　　
     In China names have very clear meanings. If a girl is called Mei, her name means "beautiful". If a boy is
called Wu, his name means "like a soldier". Names in English-speaking countries are like this too. The girl's
name Joy is probably partly chosen because the parents wish their daughter to be happy and bring joy to
others. If a girl is called Ruby, it may be because of the beautiful red precious (宝贵的) stone. 　　
     Parents often pick names that can be shortened (缩写). This can be confusing (困惑的) for Chinese
people. Parents might choose such names because they want to be able to speak to their kid in a personal
(私人的) way. 　　
     For example, a popular name is William. But William can be shortened to Will, Willy, Bill and Billy. The
same is true of the favorite old name for a girl, Elizabeth. Elizabeth can be shortened to Beth, Liza and Liz. 　　
     Another reason kids get the names they do is that parents want to name their boy or girl after someone
who is famous, such as an actor, pop star or sports personality. David is a popular name in Britain, partly
because of the fame (名气) of the footballer David Beckham.

1. The following are all popular names in U.S. at this moment EXCEPT .

[ ]

A. Emily 　　　
B. Betty 　　　
C. Emma 　　　
D. Joshua

2. The name "Mei" in China means ______.

[ ]

A. joy 　　　
B. beauty 　　　
C. grace 　　　
D. love

3. Parents in China may pick a name for their child because ______.

[ ]

A. The name can be shortened 　　
B. They want their child to be happy 　　
C. The name has a very good meaning 　　
D. They can call their child in a personal way

4. Chinese and western names ______.

[ ]

A. are totally (完全地) different 　　
B. are the same 　　
C. have some similarity (相同点) 　　
D. are not different