Relacionar Columnas Modal verbs of obligation Versión en línea Match the modal verb of obligation with the correct description of each one. por AE Nallely 1 Negative structure 2 Positive structure 3 Mustn't 4 Should 5 Shouldn't 6 Must 7 Don't have to 8 Have to Means it's not ALLOWED. Express PROHIBITION. Means something is FORBIDDEN. Expresses that something is ESSENTIAL or MANDATORY from the SPEAKER'S point of view. It is an internal, subjective and strong OBLIGATION that the speaker HIMSELF imposes. Expresses a STRONG obligation that comes from a LAW or REGULATION. Modal verb in negative form (shouldn't / mustn't / don't have to) + infinitive form of the action verb MILD negative obligation or advice. Expresses that something is a BAD idea. Modal verb + infinitive form of the action verb Is a weak obligation, and we use it to give advice. Talks about rules and regulations. The obligation does not come from the person who is speaking. Means you DON'T need to do something, but it's FINE if you want to do it.