Why horses have skinny legs? What’s the use of a skinny leg? The answer is Running. The skinniest lower legs belong to the fastest runners. Think of how a deer can move, as opposed to a tortoise. Why is that? It’s because when you run, or indeed walk, you are constantly swinging the bottom halves of your legs. For humans, one foot is stopped and essentially resting on the ground while the other is moving twice as fast as your overall speed.

为什么马的腿很细？一个瘦小的腿有什么用？答案是奔跑fUA2wRl9&Hgd9[)5ncPu。最快的奔跑着长着最细的腿属dA,_e@RMUu。想想鹿是怎样移动的，它和龟完全不一样9QN6+kwWz_h~fVdod。这是为什么？这是因为当你奔跑或行走是，你会不断摆动腿的下半部%d(IJ!Q7rk&PF&d7J。对于人类来说，一只脚已停止，实际上是停留在地面上休息，而另只脚正以整体速度的两倍移动a,J4IX,]m~-EgYhWmusA。

skinny adj. 皮包骨头的, 很瘦的
tortoise n. 龟, 行动迟缓的人
essentially adv. 实质上
overall adj. 从头到尾的; 总的