They tried to make me go to rehab
But I said 'no, no, no'
Yes, I've been black, but when I come back
In this song, we have Amy Winehouse making a promise or a strong prediction: that when she comes back we will "know-know-know". What is she saying exactly? She is making a promise and/or a strong prediction of what is going to happen when she is back.
To do that, she uses will or the abbreviated form 'll.
In English, we use different structures to deal with the future. In this text, we are going to deal with the "will"-structure.
We can use "will" for different situations:
"I will take my car to the mechanic next month. It's really bad."
"I won't ever hurt you, I promise you". (won't = will not)
"Oh, I've forgotten my pen. I'll just go downstairs and get it".
"I'm so hungry! I'll eat something".
Now, another part of the song:
He's tried to make me go to rehab
But I won't go-go-go
In this line, she is clearly making a promise: she won't go to the rehab center.
Now, imagine you're late with your homework and your teacher wants to talk to you about it. What would you tell her?
(Hints: Not - worry - do - it - tomorrow)
"Don't worry, teacher, I will do it tomorrow!"
Your boyfriend/girlfriend is talking to someone you really don't like. You tell him/her that as he/she loves you very much, what does he/she say?
"Don't worry, honey. I won't talk to her/him again!"
One more situation:
In the middle of the class, your teacher remembers she hasn't brought her bottle of water with her, and she says that outloud. Since you are a very good student (and bored), you immediately offer to fetch it for her. What do you say?
"Don't worry, teacher. I'll fetch it for you".