Important Modal Verbs and their usage

May is used for permission, probability.

May

Must indicates obligation, firm necessity, logical conclusion, probability

Must

Shall is used to show intention, supposition

Shall

Will can be used for wish, desire, future

Will

Ought to indicates moral duty, insistent advice, strict recommendation

Need is to show necessity

Have to is used to show order, unwillingness

Would indicates polite request, habit of the past, wish

Should is used to show necessity, advice, blame, recommendation, regret

Used to shows repeated action in the past

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