If your knees aren't green by the end of the day, you ought to seriously re-examine your life.

If your knees aren't green by the end of the day, you ought to seriously re-examine your life.

如果你的膝盖在一天结束的时候没有变绿，你应该认真地重新审视你的生活。

-- Bill Watterson 比尔沃特森