English Business Institute, Marcory (2026)

10/08/2016

TO HAVE TO / MUST

10/08/2016

Common Modal Verbs and their Particularities 28 min
Which verbs are common modal verbs?

Can, could, may, might, should, must, shall, will, would
How are modal verbs different from other verbs?

- They do not take “s” in the third person: he can, she must, it could
- They use “not” in the negative form: they may not, we should not
- They cannot be used in the past or in the future tenses
- There is no “to” after them: I can do, you must see

Which modal verb do we use and when?
Modal Verb Use Example
Can
Capacity I can drive.
Permission/request Can I use your phone please?

Could
Capacity in the past (past of „can‟) I could not see him.
Polite permission/request Could I use your phone please?
Suggestion We could go to the new restaurant.
Possibility, low probability or one
possibility of many
It could rain today.
She could be at home.

May
Polite permission/request May I use your phone please?
Possibility, more probable than „could‟
It may rain today.
She may be at home.
Might Same as „may‟
It might rain today.
She might be at home.
Should
Advice He should go to the doctor.
Rational probability He should be fine.
Must
Obligation, necessity You must go to school.
Very high probability She must be at home.

Shall
Obligation in legal documents The defendant shall pay a fine of $200.
Suggestions Shall we begin?
Future tense, rare, British Thou shall not kill.

Will
A voluntary action I will make dinner.
A promise I will call you at 4 pm.
A prediction The summer will be very hot.

Would
Conditional If I had time, I would travel more.
Past of „will‟ He said he would come.
Repetition in the past When I lived in Paris, I would
always go to the Champs Elysees.

Some of these common modal verbs have synonyms we often use.
Examples:

must = have to, need to
shemust leave = she has to live = she needs to leave
should = ought to
heshould speak to his boss = he ought to speak to his boss
When we speak, we use contractions with some of the modal verbs in the negative
form.
Examples:
can't = cannot = can not
couldn‟t = could not
shouldn‟t = should not
mustn‟t = must not
won‟t = will not
wouldn‟t = would not