特别广播英语第 51 课：Why We Walk in Circles 为什么我们会走成两个大圆圈-3

Then you know that it will rarely travel in a straight path. 那么，你就会知道小汽车几乎很少顺着直线跑，

It will travel, instead, in some kind of arc, or curve. If it is to travel in a straight line, the wheels on both sides have to be of exactly equal size. 那么它左右两边的车轮的大小必须是正好绝对相等的。

If they are not, the little automobile turns toward the side with the smaller wheels. 如果不走直线，小汽车就会转向小轮子的一面。

Circular movement in walking is caused in much the same way. 步行时绕大圆周运动的规律在很大程度上是由同一原理引起的。

Usually a man walking will "watch his step" and "look where he is going." 通常一个人走路时会看着脚下所踩的步子，会看着所要去的方向。

He needs his senses, especially his eyes, to get to the point he intends to reach. 一个人需要用他们的各种器官，特别是要用两只眼睛，才能走到他打算要去的地点。

When he cannot use his eyes to guide his steps, he will walk straight only if he takes a step of the same length with each foot. 只有当一个人的两只脚所迈出的每一步的长短都完全相同时，这个人才可以不用眼睛来引导脚步而能够顺着一条直线往前走。

In most people, however, muscle development is not the same in both legs, so that it is probable that the steps will be uneven. 但是，在绝大多数人左右两腿肌肉的发育并不是一样的，结果很可能左右两脚所迈的步子长短是不一致的。

The difference may be so small that no one is aware of it. But small as it is, it can cause circular movement. 迈步子长短的差距是非常小的，以致于没有人会意识到这一微小的差距。尽管这个差距很小，但结果却导致了圆周运动。

Let us suppose that a man's left foot takes a step 20 inches long and that his right foot takes a step 30 inches long. 我们假定某一人的左脚迈一步是20英寸长，右脚万一步是30英寸长。