Here's a list of the modal verbs in English:
can |
could |
may |
might |
will |
must |
shall |
should |
ought to |
Modals are different from normal verbs:
1: They don't use an 's' for the third person singular.
2: They make questions by inversion ('she can go' becomes 'can she go?').
3: They are followed directly by the infinitive of another verb (without 'to').
Probability:
First, they can be used when we want to say how sure we are that something happened / is happening / will happen. We often call these 'modals of deduction' or 'speculation' or 'certainty'
or 'probability'.
For example:
Ability
We use 'can' and 'could' to talk about a skill or ability.
For
example:
Obligation and Advice
We can use verbs such as 'must' or 'should' to say when something is necessary or unnecessary, or to give advice.
For
example:
Permission
We can use verbs such as 'can', 'could' and 'may' to ask for and give permission. We also use modal verbs to say something is not allowed.
For
example:
Habits
We can use 'will' and 'would' to talk about habits or things we usually do, or did in the past.
For
example: