It's very helpful for me, as I address you, to think about what you're seeing in the text, and that helps me to think about what I want to say to you.

这对我很有用，正如我和你们说的，想一想你们在文章里看到了什么，那会帮助我思考要和你们说什么。

耶鲁公开课 - 1945年后的美国小说课程节选

But I think, yeah, practicing in the country where this language exists is very useful.

但是我想，是的，在这个说英语的国家练习英语很有用。

学习英语的理由 - SpeakingMax英语口语达人

So the exceptions are useful when you want to have the ability to say, I expect in general this kind of behavior, but I do know there are some other things that might happen and here's what I'd like to do in each one of those cases. But I do want to make sure that I don't let a value that I'm not expecting pass through.

所以当你希望有能力说,我希望一般是这样的行为,异常是很有用的,但是我明白还有一些其它的情况可能发生,我希望对每一种情况都这么做,但是我跟希望能保证,没有让一个预期之外的情况漏过去。

麻省理工公开课 - 计算机科学及编程导论课程节选

What is useful is point to somebody and say, "You in the green sweater, call the police," and the psychological evidence is if you--if somebody's-- if I am wearing the green sweater and somebody asks me to call the police I will call the police. I'm a good guy.

有用的办法是，指着某个人说，“穿绿色毛衣那个人，快报警”,心理学证明如果你…,如果我穿着绿色毛衣,有人叫我报警,我会报警，我是好人。

耶鲁公开课 - 心理学导论课程节选

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