鸭子的脚长有游泳用的蹼。

Ducks have webbed feet to help them swim.

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它是一种蜗牛，脚部已经进化成为一对游泳用的翅膀。

Aptly called a sea angel, this translucent creature is a snail whose foot has been modified into a pair of swimming wings.

youdao

人们形象地称这种透明生物为海天使。它是一种蜗牛，脚部已经进化成为一对游泳用的翅膀。

Aptly called a sea angel, this translucent creature is a snail whose foot has been modified into a pair of swimming wings.

youdao