在离太阳15 光年的范围内有大约56 颗恒星，分布在38 个恒星系中。以上推论都是大概的，因为如下原因。

Within 15 light-years of the sun there are approximately 56 stars, in 38 separate stellar systems. I say approximately for several reasons.

youdao

原因如下：如果你看到某人做某事做得很好，你会说这是因为他们有天赋。

Here's why: if you see someone doing something really well, you would say it's because they are talented.

youdao

原因如下：试图抓住市场是愚蠢的。因为有一个买家，就有一个卖家。

Here's why: Trying to time the market is folly because for every buyer, there is a seller.

youdao

We're, as a consequence, going to focus on worst case. This is handy for a couple of reasons.

因此我们会去关注最坏的情况,因为如下的原因这样做。

麻省理工公开课 - 计算机科学及编程导论课程节选