There is another kind of auxiliary verb. This is called a modal auxiliary verb or simply known as «the 9 modal verbs».
can, could, may, might, must, shall, should, will, and would.
MODAL VERBS express many things such as;
ABILITY can / could
PERMISSION can / could / may
ADVICE / SUGGESTIONS could
OBLIGATIONS must / mustn’t
POSSIBILITY might / may / could
UNCERTAINTY / CERTAINTY must not / must
WILLINGNESS / REFUSAL wouldn’t
REQUEST / OFFER will / shall / could / would / can
POSSIBLE OR IMPOSSIBLE could / could not / couldn’t
QUESTIONS. can i ? could i ? may i ?
INVITATIONS AND OFFERS. would / shall / can
- The infinitive comes after the modal verb but without the «to». He should pay us.(correct). He should to pay us. (incorrect)
- The form stays the same. They do not change their form according to tense. (past, present or future tenses )
- Just use «not» to form the negative. can not would not might not
- Modal verbs take off the «S» in the third person singular.
Can Could May Might Must Shall Should Will Would
Can / Cannot / Can't
Can is used to state what is generally possible. For example; I can burn my hand if it gets too close to the fire.
Ability. I can skydive without feeling afraid. I can’t drive a car very well.
Impossible. I can’t seem to make friends easily.That can;t be the house of Maria as she lives in the next street.
Informal. Can i stay at your place for the holidays?
Offers. Can i help you with the shopping bags?
Could / Could not / Couldn't
Question. Could we meet at 9am?
Requests. Could i have a table near the window please.
Possible / Not possible. It couldn’t rain in the desert, could it?
Advice / suggestion. You could retake the exam at another date.
Suggestion. They could attempt to climb the mountain when the weather is better.
Semi-informal. Could i have your contact details?
May / May not
Possibility. It may snow today.
Permission. You may go to the toilet at coffee break.Pensioners may travel for free on the new metro.
Formal. May i borrow some money from you?
Might / Might not / Mightn't
Possibility. He might be coming later. She might be on the same train as us.
Questions. Might i borrow your umbrella as it is raining?
Must / Must not / Mustn't
Assumed situation or probability. She is so clever. she must have high exam grades.
Not allowed. You must not talk in the library.
Necessity. I must see a doctor as i feel unwell.
Obligations. You must driving slowly in the pouring rain.
This is a library so you mustn’t make any noise.
Shall / Shall not / Shan't
Offers and invitations. Shall we help our elderly neighbour with the shopping?
Promises. I shall make sure my son has a great birthday.
Should / Should not / Shouldn't
Recommend and best approach. We should try the new ice cream parlour on London street. You should go home now before it gets too dark.
Will / Will not / Won't
Commitment or promise. I will go to Disney world this year.
Questions. Will «raving storm» win the horse race again?
Would / Would not / Wouldn't
Desires. I would love to learn to surf.
Preferences. Would you like to sit down or stand up?
Requests. Would you paint this door for me please?
Invitations. Would you like to come to my birthday party on Saturday. Would you all like to come to lunch with the company today.