◊ GRAMMAR
Modals are a type of auxiliary verb. They are used, for example, to indicate the possibility or necessity of an event, and to make requests, offers, and suggestions. They can also be used to make what you are saying more tactful or polite.
\
The following words are modals:
can, could, may, might, must, ought, shall, should, will, would
\
A modal is always the first word in a verb group. All modals except `ought' are followed by the base form of a verb (the infinitive without `to'), unless the verb has already been mentioned (see entry at ↑ Ellipsis).
I must leave fairly soon.
Things might have been so different.
People may be watching.
`Ought' is followed by a `to'-infinitive.
She ought to go straight back to England.
Sam ought to have realized how dangerous it was.
Modals have only one form. There is no `-s' form for the third person singular of the present tense, and there are no `-ing' or `-ed' forms.
There's nothing I can do about it.
I'm sure he can do it.
◊ short forms
`Shall', `will', and `would' are not usually pronounced in full. When you write down what someone says, or write in a conversational style, you usually represent `shall' and `will' using 'll, and `would' using 'd, after pronouns. See entry at ↑ Contractions.
I'll see you tomorrow.
Posy said she'd love to stay.
You can also represent `will' as 'll after a noun.
My car'll be outside.
◊ WARNING
`Shall', `will', and `would' are never shortened if they come at the end of a sentence.
Paul said he would come, and I hope he will.
Remember that 'd is also the short form of the auxiliary `had'.
I'd heard it many times.
The auxiliary `have' is not usually pronounced in full after `could', `might', `must', `should', and `would'. The contractions `could've', `might've', `must've', `should've', and `would've' are occasionally used in writing when reporting a conversation.
I must've fallen asleep.
You should've come to see us.
`Not' is not usually pronounced in full after a modal. You usually represent what someone says using 'nt after the modal. See entry at ↑ Contractions.
\Useful english dictionary. 2012.