MODALS, SEMI-MODALS AND PERFECT MODALS

Modals, semi-modals and Modal Perfect.

MODALS

• Can: General ability in the present or future, informal request, permission.
• Can't: Impossibility or something hard to believe.
• Could: General ability in the past (past form of can),possibility (not certain), request, suggestion.
• Couldn´t: Inability.
• May: Possibility in the present or future, formal request (with I/we), formal permission or lack of permission (may not).
• Might: Possibility in the present or future, negative possibility, past form of may.

• Must: Strong necessity, obligation, near certainty, suggestion, recommendation.
• Mustn't: Prohibition
• Should /ought to: advice, opinion, polite suggestion (with I/we), prediction.
• Will: polite request.
• Would: polite request, repeated past action, past form of will.
• Wouldn't: refusal or impossibility.
• Shall: polite question, offer, suggestion (with I/we)

SEMI-MODALS

• Be able to: general ability=can (it can be used in all tenses), specific past ability/managing to do something despite difficulty or successful result.
• Have to/ has to: obligation or necessity (have to can be used in different tenses to express the past and future of must)
• Don't/ doesn't have to: lack of obligation or necessity (similar to needn't)

MODAL PERFECT

• May/might/could have + past participle: when we are not sure what happened in the past.
• Could have + past participle: when we have the ability / opportunity to do something in the past but did not do it.
• Would have + past participle: willingness to do something, but didn't do it.
• Can't have + past participle: when we are sure that something did not happen.
• Must have + past participle: when we are certain that something happened in the past.

• Should/ ought to have + past participle: when expectations were not fulfilled/ advice was not followed/ showing regret about something.
• Needn't have + past participle: when we want to express that there was no obligation or necessity to do something.

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