And in fact, one of the lessons you may already be realizing with P sets is that things seem to take twice, three times, four times longer than you actually might think.

从习题集中你可能已经得出的一个教训就是,程序所花的实际时间往往是你开始以为的两倍，三倍，四倍甚至更长。

哈佛公开课 - 计算机科学课程节选

- So now we have three conditions -- three forks in the road -- and this program is in fact correct, at least hopefully.

现在我们有三个条件--三岔路口-,然后这个程序的确是正确的，至少我希望是。

哈佛公开课 - 计算机科学课程节选