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光电管,一种非常特殊的电子管,是有声电影放映机的心脏。
The phototube, a very special type of electron tube, is the heart of the talking-picture projector.
youdao
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光电管,一种非常特殊的电子管,是有声电影放映机的心脏。
The phototube, a very special type of electron tube, is the heart of the talking-picture projector.
youdao