下列关于电磁波的说法正确的是

【名词&注释】

电磁波(electromagnetic wave)、直线传播(rectilinear propagation)、蝶形花冠(papilionaceous corolla)

[单选题]下列关于电磁波的说法正确的是

A. 均匀变化的磁场能够在空间产生电场
B. 电磁波在真空和介质中传播的速度相同
C. 只要有电场和磁场，就能产生电磁波
D. 电磁波在同种介质中只能沿直线传播

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学习资料：

[单选题]DWhen students and parents are asked to rate subjects according to their importance, the arts are unavoidably at the bottom of the list. Music is nice, people seem to say, but not important. Too often it is viewed as mere entertainment, but certainly not an education priority(优先). This view is shortsighted. In fact, music education is beneficial and important for all students.

A. Music tells us who we are. Because music is an expression of the beings who create it, it reflects their thinking and values, as well ad the social environment it came influence that George Gershwin and other musicians introduced into their music is obviously American because it came from American musical traditions. Music expresses our character and values. It gives us identity as a society.
B. Music provides a kind of perception(感知)that cannot be acquired any other way. Science can explain how the sun rises and sets. The arts explore the emotive(情感的)meaning of the same phenomenon. We need every possible way to discover and respond to our world for one simple but powerful reason: No one way can get it all.
C. The arts are forms of thought as powerful in what they communicate as mathematical and scientific symbols. They are ways we human beings “talk” to each other. They are the language of civilization through which we express our fears, our curiosities, our hungers, our discoveries, our hopes. The arts are ways we give form. to our ideas and imagination so that they can be shared with others. When we do not give children access to an important way of expressing themselves such as music, we take away from them the meanings that music expresses.
D. Science and technology do not tell us what it means to be human. The arts do. Music is an important way we express human suffering, celebration, the meaning and value of peace and love.
E. So music education is far more necessary than people seem to realize.
F. regardmusicasawayofentertainment
G. disagreewiththeirparentsoneducation
H. viewmusicasanoverlookedsubject
I. prefertheartstoscience

[单选题]I agree to his suggestion the condition that he drops all charges.

A. by
B. in
C. on
D. to

[单选题]

A. writen
B. sulfered
C. observed
D. lost

[多选题]假蝶形花冠与蝶形花冠的区别在于( )不同。

A. 花瓣数目
B. 花瓣形态
C. 花瓣排列方式
D. 花瓣色彩
E. A和C

[单选题]子房基部着生在花托上，花的其他部分都低于子房着生，这种花叫做( )。

A. 上位子房下位花
B. 上位子房周位花
C. 下位子房上位花

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