题干

关于能源和能量,下列说法中正确的是    (    )

A:自然界的能量是守恒的,所以地球上能源永不枯竭

B:能源的利用过程中有能量耗散,这表明自然界的能量是不守恒的

C:电磁波的传播过程也是能量传递的过程

D:在电磁感应现象中,电能转化为机械能

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C

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    Imagine that you're the creator and show runner of the newest comedy show on television. Only it isn't so popular yet, and your live Studio audience isn't giving you the big laughs the show deserves. Do you film the show all over again, hoping that this time the audience will laugh? Or is there another option for making a joke sound funnier than it was received?

    Sweeten(改善) the sound by adding a laugh track! “Sweetening,” or the addition of sound effects such as laughs, screams, and other audience-produced noises to the audio track of a TV show, has been used since the 1940s to produce the appearance, or rather the sound, of an engaged and entertained response to a show's comedy. Laugh tracks came into existence as not only a solution, and sometimes replacement, for an unengaged live audience but also as a way to engage an at-home audience into a more-traditional, public, and theaterlike experience. Adding a laugh track to a television show makes the viewers at home feel much less like they're sitting on a couch staring at the television screen and much more like they're in a room full of laughing happy people to varying degrees of success.

    Though the art of sweetening has risen and fallen in popularity over the past 60 years, credit for its creation and continued use is owed to laugh-track pioneer and sound engineer Charles Douglass. Douglass was the first to develop, in 1953, a machine for producing “canned laughter”, accessible at the push of a button or pull of a lever (操纵杆). Despite being artificial, sensibly edited laugh tracks are found by television studios to bring about a positive audience response, as their use is usually accompanied by higher ratings and increased audience memory. Though some television audiences may disagree with the value of the laugh track, the cheerful and repetitive sound holds a permanent place in the history and future of television comedy.