UNIT 9: GRAMMAR
MODALS AND SEMI-MODALS
• The nine mains modal (will, would, can, could, may, might, shall, should, must) have only one
form (ie they do not change tense or person so we followed by a simple or continuous bare
infinitive (eg could + do, being doing, have done, have been doing !) they can also be followed by
the bare infinitive in the passive (could + be done, have been done)
• Semi-modals has similar meaning to modal. They include: need (to), ought to, had better and
have (got) to.
• Some semi-modals, such as had better, do not change tense or person. Others, such as have (got)
to, do.
• Some semi-modals can be used in combination with modals. Producing phrases such as might
have to.
Ability
Real ability
Current or general ability
Past ability
Decisions made now about
future ability
Future ability
Can, can't
Could, couldn't
Can, can't, could,
couldn't
Will/won't be
able to
You can't speak seven languages
fluently, can you ?
There's no way you could read
when you were two !
I can get you a paper when I go
to the shop, if you like.
One day, may be all adults will
be able to read and write.
Hypothetical
ability
Current or general
hypothetical ability
Future hypothetical ability
Past hypothetical ability
Could, couldn't
Could, couldn't
Could have,
couldn't have
I couldn't go on a quiz show, I'd
be too scared !
I could go with them to the
cinema tomorrow but I won't
because I've already seen the
film.
They could have asked the
Prime Minister much more
searching question, I wonder
why they didn't.
Watch out
• The full negative form of modals is written as two words, eg could not. The exception is cannot,
which is one word.
• Can and could cannot be used is infinitives. We can use to be able to instead.
I'd love to be able to come with you to the cinema tomorrow but I just can't.
• We don't usually use could for past ability on one occasion. We use was/were able to, managed
or succeeded, etc.
Luckily, she was able to finish the article in time.
However, with verbs such as see, hear, feel, etc we can use could for past ability on one occasion.
I could see that she was tired.
Permission
Asking for permission
May, could, couldn't, can, can't
Can I finish watching this
