So in other words, if thankful is still false at this point, it means this condition did not work out very well, and so I'm going to do this block of code again.

换句话说，如果thankful在这时候还是false值，这表示这个条件没有实现地很好，所以我将再次去处理这段代码。

哈佛公开课 - 计算机科学课程节选