Well, you'll know when it crashes, that doesn't help you very much, but you can't always tell whether something's stuck in an infinite loop or whether it's simply taking a long time to compute.

好，你将学到它在什么时候会崩溃，这对你帮助并不大，但是你不能辨别出到底是在一个循环中,有什么东西卡住了呢,还是程序需要很长的时间来计算一个结果呢。

麻省理工公开课 - 计算机科学及编程导论课程节选