你需要知道一些有用的信息。

You need to know some useful information.

youdao

“雨”和“在门口”可能会给你一些有用的信息。

"Rain" and "in the doorway" might give you helpful information.

youdao

我们将提高准确率并为这个虚构的经销商提供一些有用的信息。

We're going to improve it and give this fictional dealership some useful information.

youdao

But notice what this does. The first thing it does is, it says, let's check and make sure x is greater than or equal to 0. If it isn't, notice what's going to happen. None of that block is going to get executed, and it's going to come down here and print out a useful piece of information, which says, hey, you gave me a negative number. I don't know how to do this.

做的是和以前一样的事情,但是注释它做了什么，第一件做的事情就是,程序说，要去检查并且确信x是大于等于0的，如果不是的话，请注意会发生什么,下面的代码都不会被执行,程序会到这里来然后显示一些有用的信息,信息会说，嘿，你给了我一个负数,我不知道该怎么弄这个了。

麻省理工公开课 - 计算机科学及编程导论课程节选