英语听力文摘 English Digest 264、马腿为什么那么瘦？

　　Skinny Legs and All
Why do horses have skinny legs? Find out on this Moment of Science.
Why do horses have skinny legs?
Okay, they aren’t entirely¹ skinny — it’s mostly the (1)bottom half, with a big muscle up at the top.That’s odd. Human legs are kind of like that too — bigger on the (2)top half. Come to think of it, dogs’ legs are like that. And cat legs. Wait a minute. Deer legs are really skinny on the bottom and much thicker at the top. Antelopes². Gazelles. Giraffes. Elephants.
No, wait. Elephant legs aren’t really like that. Neither are duck legs, or panda bear legs. So it can’t be a prerequisite³ for any leg. What’s the use of a skinny leg?
Answer? Running. The skinniest lower legs belong to the fastest runners.Ok,so 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 essentially⁴ resting on the ground while the other is moving twice as fast as your overall speed. Then that foot stops and the other one accelerates. And so on.
Thinner, lighter⁵ things are easier to accelerate than heavy, massive ones. So if you want speed, put the muscles up high and the skinny down low. If you really want speed, you could even go further and (3)pare down the foot, to decrease lower leg mass even more. A few million years of evolution and you’ll (4)wind up with…you guessed it. A hoof⁶.
Notes:
(1)bottom half 下半区（抽签）；下半部分
Then put the hamburger on the bottom half of the hamburger bun.
然后把牛肉饼放在下面半个汉堡面包上面。
(2)top half 上半部；顶部
The lower half apparently⁷ does not matter, but the top half is sacrosanct⁸ .
下半口显然不要紧，但上半口则是神圣不可侵犯的。
(3)pare down 减少；削减
It will be necessary to pare this budget down considerably⁹.
有必要大大地削减这笔预算。
(4)wind up with 以 ... 结束
I love waking up in the morning and not knowing what's going to happen,or who i'm going to meet,where i am going to wind up.
我喜欢早上一起来是一切都是未知的,不知会遇见什么人,会有什么样的结局.

1 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

2 antelopes   

羚羊( antelope的名词复数 )； 羚羊皮革

参考例句：

• One jump, and you're out, and we'll run for it like antelopes.' 你只要一跳就出来了，我们可以像羚羊那样飞快地逃掉。”
• Most antelopes can withhold their young for weeks, even months. 绝大部分羚羊能把分娩期推迟几个星期，甚至几个月。

3 prerequisite   

n.先决条件；adj.作为前提的，必备的

参考例句：

• Stability and unity are a prerequisite to the four modernizations.安定团结是实现四个现代化的前提。
• It is a prerequisite of entry to the profession that you pass the exams.做这一行的先决条件是要通过了有关的考试。

4 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

5 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。

6 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。

7 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

8 sacrosanct   

adj.神圣不可侵犯的

参考例句：

• In India,the cow is a sacrosanct animal.牛在印度是神圣的动物。
• Philip Glass is ignorant of establishing an immutable, sacrosanct urtext.菲利普·格拉斯不屑于创立不变的、神圣的原始文本。

9 considerably   

adv.极大地；相当大地；在很大程度上

参考例句：

• The economic situation has changed considerably.经济形势已发生了相当大的变化。
• The gap has narrowed considerably.分歧大大缩小了。