蝙蝠的翼是演化过程中由前肢演化而来。除拇指外，前肢各指极度伸长，有一片飞膜从前臂、上臂向下与体侧相连直至下肢的踝部。

Their wings are evolutionary modification of the forelimbs, with greatly elongated fingers joined by a membrane that extends down the side of the body.

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蝙蝠的翼是演化过程中由前肢演化而来。除拇指外，前肢各指极度伸长，有一片飞膜从前臂、上臂向下与体侧相连直至下肢的踝部。

Their wings are evolutionary modification of the forelimbs, with greatly elongated fingers joined by a membrane that extends down the side of the body.

youdao