她本应该知道不该吃那么多。

She should have ___known ___better than to eat so much.

我本应该知道不该那样做，但我不得不告诉别人。

I should have ___known ___better but I had to tell it to someone.

孩子们应该知道不该玩火。

Children should ___know ___better than to play with fire.