英语时差：马的腿为什么这么细？

Then that foot stops and the other one accelerates. And so on. Thinner, lighter things are easier to accelerate than heavy, massive ones. So if you want speed, put the muscles up high and the skinny down low. Speed If you really want speed, you could go even further and pare down the foot, to decrease lower leg mass even more. A few million years of evolution and you’ll wind up with…you guessed it. A hoof.