but if you explain it to your friend that you or she should not have or should have done something,

如果你想要向你的朋友解释，或者她应该做某事的时候，

I should have 课堂 - SpeakingMax英语口语达人

Or "you need to do something" or "you need not to do something".

或者“你应该做某事”或“你不应该做某事”。

I'm sure 课堂 - SpeakingMax英语口语达人