在俯卧姿势，将骨盆转到右边然后再到左边。

In the prone position, turn your pelvis to the right and then to the left.

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蝶泳：一种泳姿。即采用俯卧姿势，双臂同时在水面之上前挥划水，结合身体做海豚式打水。

Butterfly: a stroke made in the prone position where both arms are lifted simultaneously out of the water and flung forward, in combination with the dolphin kick.

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