【英语时差8,16】马的腿为什么这么细？

 Then that foot stops and the other one accelerates. And so on. Thinner, lighter¹ 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 hoof².

1 lighter   

n.打火机，点火器；驳船；v.用驳船运送；light的比较级

参考例句：

• The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
• The lighter works off the car battery.引燃器利用汽车蓄电池打火。

2 hoof   

n.(马，牛等的)蹄

参考例句：

• Suddenly he heard the quick,short click of a horse's hoof behind him.突然间，他听见背后响起一阵急骤的马蹄的得得声。
• I was kicked by a hoof.我被一只蹄子踢到了。