题干

如图,关于声音的四幅图片的说明,正确的是(  )

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A:图片a中的蝙蝠利用发出的电磁波导航

B:图片b表明月球上的宇航员能直接交谈

C:图片c所示的隔音墙表明噪声可以在声源处减弱

D:图片d表示声音是由发声体的振动产生的

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答案(点此获取答案解析)

D

同类题1

Values join us together and set us apart. Today, our society has a terrible lack(缺乏)of values. Here are some social values that everyone needs.
◆Respect
Respect means to respect(尊重)others in everyday life. Even if you are against a person, it is important to have respect. It is this respect that makes us human. Without this respect, we become  animals. We need to respect our friends for our friendships. We even need to respect our enemies, because they help us to grow up and be stronger. Respect is one of the crucial values in a relationship.
◆Love
Love is everything. With love in our hearts, we feel no need to hurt another. With love in our hearts, we will pay more attention to the similarities in opinions rather than the disagreement. If we want others to be good to us, we need to be good to them. After all, we give love to get love, right?
◆Loyalty
People often forget the meaning and importance of loyalty(忠诚). Loyalty is necessary for people to believe in each other. In no matter what kind of relationship, we need to believe in each other so that we can work together towards the same goal.
◆Honesty
Honesty is to show other people who we really are. Honesty helps us do better, because it makes us realize our problems and find ways to solve them. It is this honesty, that will make others help you out, not because you need it. But, because they have problems too, which you can help out with. This honesty will help us follow the other values in society and, truly, "heal the world"!