ENGLISH V

Jonathan Morales Hernández

Modal auxiliary verbs: MUST

Jasso Martínez Luis Gerardo

Méndez Álvarez Iván Daniel

Universidad Politécnica de Victoria

Must (Subjetive obligation)

We often use must to say that something is essential or necessary.

Must express obligation or necessity.

Examples:

I must go. You must pay. We must study.

Must is a modal auxiliary verb. It is followed by a main verb. The structure is:

subject + must + main verb

The main verb is the base verb (infinitive without "to").

Structure of Must

Look at these examples:

Grammar

Affirmative Negative Interrogative

I must pay I mustn’t pay Must I pay?

You Must pay You mustn’t pay Must you pay?

He must pay He mustn’t pay Must he pay?

She must pay She musn’t pay Must she pay?

It must pay It mustn’t pay Must It pay?

We must pay We mustn’t pay Must we pay?

They must pay They mustn’t pay Must they pay?

Must in Present, Past and Future.

We only use 'must' in the present. For all other tenses we use 'have to'.

Must NEVER is used with other auxiliary verbs such as do, does, did etc. The negative is formed simply by adding "not" after the verb; questions are formed by inversion of the verb and subject.

Must NEVER is followed by to.

Must NEVER change the form: you can never add an "-s" or "-ed", for example.