Matching Pairs Must have toOnline version The correct use of must , have to and their negative form by Sabs Negrete 1 A personal very important, necessary thing to do 2 Formal or written obligations 3 Forbidden or not allowed to do 4 Not necessary and you can choose 5 You have no choice. 6 It is an obligation from the situation. 7 It isn't necessary, just and advice SHOULD & SHOULDN'T MUST MUST NOT MUST HAVE TO DON'T HAVE TO HAVE TO