to know right from wrong meaning in English

辨正邪, 明善恶, 辨是非

It is not always easy to know right from wrong
分辨是非并不总是很容易的。
In order to show the realistic significance of the theme of adherents of ming dynasty , the following warning significances for the present should be made clear : official should regulate themselves ; official and masses unified as one , every profession will be prosperous ; and to know right from wrong is to keep virtues
为了凸现明遗民论题的现实意义，还可以申论明遗民的警世意义：士之为士，规范自尊；士民不分，百业可从；是非分明，不失操守。