Tema: Modal Auxiliary Verbs: Must. Asignatura: English V. Universidad Politécnica de Victoria. 2012

1. ENGLISH V
Jonathan Morales Hernández
Modal auxiliary verbs: MUST
Jasso Martínez Luis Gerardo
Méndez Álvarez Iván Daniel
Universidad Politécnica de Victoria

2. Must (Subjetive
obligation)
We often use must to say that
something is essential or necessary.
Must express obligation or necessity.

3. Examples:
 I must go.
 You must pay.
 We must study.

4. 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

5. Look at these examples:

6. 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?

7. Must in Present, Past and
Future.

8.  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.

9.  Must NEVER is followed by to.
 Must NEVER change the form: you can
never add an "-s" or "-ed", for example.

10.  Must NEVER is followed by to.
 Must NEVER change the form: you can
never add an "-s" or "-ed", for example.