他们听上去都是拟声词flip音节短促尖锐 用以描述快捷疾速的动作.flip-flop的发音模拟快速往复的动作.flap听上去不正象旗帜和船帆在风中拍打的声音吗?

"Flip" is a short, sharp word for a short, sharp action. "Flip-flop" arose in imitation of the action of going quickly back and forth.

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要生产泵动作用，它包括往复运动的活塞或旋转叶片。

To produce the pumping action, it contains pistons that are driven back and forth, or rotating vanes.

youdao

要生产泵动作用，它包括往复运动的活塞或旋转叶片。

To produce the pumping action, it contains pistons that are driven back and forth, or rotating vanes.

youdao