Only later might their arms have evolved into wings they could push up and down, transforming them from gliders to true powered fliers.

尔后，前肢进化成可以上下拍动的翅膀，于是它们又从滑翔者转型成为真正的飞行家。

youdao

Gliders are of course symmetrical in design, so there are actually only around 200 different individual panels as the two sides are simply mirror images of each other.

滑翔伞当然是对称设计的，所以事实上只有大约200个不同的单独的面板，因为两个边就是彼此影像的镜子。

youdao

Gliders are of course symmetrical in design, so there are actually only around 200 different individual panels as the two sides are simply mirror images of each other.

滑翔伞当然是对称设计的，所以事实上只有大约200个不同的单独的面板，因为两个边就是彼此影像的镜子。

youdao