精选英文背诵：你有一个选择

　　You Have a Choice

　　你可以选定一种解释

　　Two trains are traveling side by side and at the same speed along paralleltracks. We are seated in one of the trains, and with us we have a special speedometer that measures their relative speed. Since the trains are traveling at the same speed, their relative speed is zero; the speedometer therefore reads "0."

　　两列火车以相同的车速并排地沿着两条平行的轨道往前行驰。我们坐在其中的一列火车上带着特制的速度测量仪，可以测出两列火车之间的相对速度。因为这两列火车是以相同的车速前进的，所以二者的相对速度是零;因此，测速仪上的读数为"0"。

　　Suddenly the other train seems to start pulling ahead of ours. The speedometer shows a reading of 10 miles per hour. The other train has apparently increased its speed. But can we be absolutely certain of this increase?

　　突然间另一列火车使我们觉得好像是开始赶到我们所乘坐的火车前头去了。这时测速仪上显示出来的读数是每小时10英里。很显然，另一列火车已经加快了速度。但是，我们能不能肯定是另外那辆火车加快了速度呢?

　　If your answer is yes, you are wrong. You are wrong because all that we know is that the relative speed between the two trains changed from 0 mph to 10 mph. Nothing more. This change could have been brought about in one of two ways:

　　The other train increased its speed.

　　Our train decreased its speed.

　　如果你回答说是的，那你就错了。你之所以是错了，我们所知道的仅仅是这两辆火车之间的相对速度由每小时0英里增加到了每小时10英里。仅此而已，这车速的变化很可能是由于下列两种原因中的任何一个原因所造成的：

　　另一列火车增加了车速;

　　我们的火车降低了车速。

　　There are thus two possible explanations to account for the change in speed, but we don't know which one is right. Furthermore, regardless of which explanation we choose, the end result will be the same: the other train will arrive at the station first. So it makes no difference whether we say that the other train increased its speed or that our train decreased its speed.

　　因而对于车速的改变就可能有两种不同的解释，但是我们不知道哪一种解释是对的。进一步来说，不管我们选定了上述两种解释中的哪一种，反正最终的结果是同样的：另一列火车将首先抵达终点站。所以，不论我们说另一列火车加快了车速，还是说我们所乘的火车减慢了车速，实际上这两种说法没有什么区别。

　　Since both explanations lead to the same result, you can choose either one. Whenever two things are relative, you can choose either one of them. The converse is also true: whenever you have a choice between two things that are equally possible, then the things are relative.

　　既然上述两种解释会导致同样的结果，那么你选定任何一种解释都可以。不论任何时候，只要两件事物两种情况是相对的，那你就可以选定其中一种解释。逆真理亦真，每当你从有同样可能的两件事物中选定其中之一时，那么这两种事物之间就是相对的。

　　There is no reason, except convenience, for choosing one explanation over the other. The relative speed between the trains remains the same, 10 mph; and the end result will be the same.

　　除为了方便这个理由而外，我们选定了一种解释而不选另一种解释根本就没有其他别的原因。如果两列火车之间的相对速度依然相同，都是每小时10英里，那么最终的结果也会是相同的。