This use shows that one thing happens earlier than another. It talks about time order in a simple way.
I ate breakfast before school.
She came before the meeting started.
Used in legal or formal situations to mean standing or appearing in front of a group or official.
She appeared before the court today.
The witness spoke before the judge.
This use talks about something that happened at an earlier time, without naming an exact event.
He lived in London before.
I have seen that movie before.
Used alone as an adverb to say that something happened at some earlier time.
I have been here before.
He told me that story before.