Well frog stays in well from its birthday to its death. The sky it can see as just as big as the mouth of the well. So people also laugh at its ill-informedness and narrow view.

井里的青蛙自打出生就一直呆在井中，它所看到的天也只是井口那么大，于是人们又嘲笑它是知之甚少，坐井观天。