MODAL VERBS

The modal verbs are auxiliary verbs. There are many modal verbs that express different things:

ADVICE	LACK OF NECESSITY	CERTAINTY	POSIBILITY
Should	Don´t have to	Can´t	May
Ought to	Needn´t	Must	Might
Had better	Don´t need to		Could

HABILITY	OBLIGATION	PERMISSION
Can	Must	Can
Could	Have to	Mustn´t
		Can´t

STRUCTURE WITH THE REPHRASINGS:

Modal verb+ infinitive

*Sometimes, when we see some expressions we know immediately what modal verbs we should use:

            -Perhaps… à May/Might/Could

            -It’s possible… à May/Might/Could

            -I’m sure… à Must

            -It’s impossible… à Can’t

            -If I were you… à Should/Ought to/Had better

            -Something+ is forbidden…à Mustn’t

            -It isn’t necessary…à Don’t have to

EXERCISES OF MODAL VERBS:
http://mbonillo.xavierre.com/exercises/bch2/2bch2008/modalrph2bch1.htm
http://www.xtec.cat/~ogodoy/sac/rephrasing/modalsex1.htm