UNIT 13
GRAMMAR
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Modals: ability, permission, advice, criticism, obligation and necessity, degrees of
certainty
Form • All modals (will, would, shall, should, can, could, may, might,must) and the semi-
modal ought to have only one form.
• Modals are followed by the bare infinitive (simple or continuous) or the bare perfect
infinitive eg Toby should be very fit by now.
Toby should have recovered by now.
• The semi-modals have to and need to change their form depending on person and tense
eg The doctor said I had/needed to give up red meat.
Modals: ability
Use
Modal
Example
Expressing ability now or generally
can
I can run a kilometre in four minutes.
Expressing decisions made now
about future ability
can
We can meet at the gym tomorrow, if you like.
Expressing ability in the past
could
I could do fifty press-ups with one hand when 1
was younger.
Expressing ability in present, future
or general hypothetical situations
could
If only I could quit smoking!
Expressing ability in past
hypothetical situations
could +
perfect
infinitive
I could have roasted the potatoes, but 1 decided
that boiling them was healthier.
We use be able to for the infini tive and other tenses.
√ I’d love to be able to fit into these jeans again! (infinitive)
√ I’ll be able to leave hospital in a few weeks, apparently, (future)
√ I've been able to swim since 1 was five, (present perfect)
Modals: permission
Use
Modal
Example
Asking for and giving permission
now, for the future or generally
may
could
can
May / Could / Can I see the doctor, please?
May is more polite than could, and could is more polite than can.
We don't usually use a modal to talk about past permission.
√ I was allowed to wear a knee support during the match.
X I could wear a knee support during the match.
However, we do use could to talk about past permission in reported
speech.
√ The coach said I could wear a knee support during the match.