Modal auxiliary verbs such as can, must and will
allow us to express concepts such as “ability” and “obligation”. We also use
them to allow us to perform a wide range of functional tasks, such as making
requests or speculating. The context in which modal verbs appear is important
as each modal has a number of different uses.
Some modals do
not have a future or past form.
We can´t use two modals together.
1) Can (infinitive to be able)
We use can
-
To talk about abilities:
She can skate
beautifully.
-
To ask for permission:
Can I borrow
your dictionary?
-
For requests:
Can you lend
$10?
ü
Remember:
The infinitive form of can is to be able to:
I may be able to
attend.
The simple past of can is could or was/were able to:
He could drive
before the accident. / He was able to drive before the accident.
2) Could
As well as being the past form of can we use could
-
To discuss alternatives and opinions:
We could invite
everyone to a restaurant, or else we could have a picnic on the beach.
-
To make more polite requests:
Could you bring
me the bill, please?
Could you speak
a little more slowly, please?
-
We use can for speculating, guessing and
discussing possibilities:
The weather
could be better tomorrow. (It´s possible)
-
Could or was able to
-
We use could to talk about general past
abilities
He could run for
miles when he was younger.
However, if we want to say we succeeded in doing
something on a particular occasion, or after a lot of difficulty we use be able
to:
I drove around
for forty minutes, finally I was able to find somewhere to park.
3) Must
We use must
-
For orders we give to ourselves:
I must pay the
phone bill, otherwise they will cut me off.
-
To prohibit something (used in mainly
written rules and regulations):
You mustn´t
speak on your mobile when you´re driving.
ü
Remember
Non-native speakers can over-use must. It can sound
rude or aggressive. To give orders, or to describe duties use have to instead.
Make polite requests with could you? instead.
-
For a strong recommendation:
You must see the
new James Bond film, it´s wonderful.
-
For making intelligent guesses and
deductions:
She must be
Melanie´s twin sister. They are almost identical.
-
For deductions in the past we use must
have been / can´t have been:
He must have
been disappointed not to pass. His teacher can´t have been pleased either.
-
For negative deductions we use can´t be,
not mustn´t be:
My parents want
me to revise all weekend – they can´t be serious! (NOT: They mustn´t be
serious.)
4) Have to
We use have to:
-
To talk about our duties or obligations
I have to deal
with phone calls and enquiries and give advice to students.
-
To show that something isn´t obligatory
or necessary:
You don´t have
to bring a dictionary to school, we have one in every classroom.
5) May
We use may:
-
To talk about possibility
It may rain this
afternoon.
-
To ask for permission
May I use your
phone?
ü
Remember
“May I” is
generally considered more polite than “Can
I”.
6) Might
We use might
-
To express a more remote possibility
than may, and to speculate.
It might be
difficult to get a baby-sitter.
-
As a very polite or formal way of asking
for permission, or making a request
Might I say
something here?
Might I borrow
your phone book for a minute?
7) Will
We use will
-
For making predictions and talking about
the future
-
When we make offers or decisions as we
speak
Leave the
washing up. I´ll do it later.
Q: Can someone
answer the door?
A: I´ll go.
-
To talk about habitual actions
Most days, I´ll
normally take the 7:42 train to Marylebone.
-
To make requests or give orders
Will you drop me
off in front of the bus station, please?
ü
Remember
Shall can
sometimes be used instead of will.
In informal, or more old-fashioned English, when the
subject of the modal is I or we, we can use shall, although this is quite rare.
I shall give you
my decision in the morning.
Shall is more
commonly used with I and we for offers, or to ask for suggestions.
Shall I answer
the phone?
What shall we do
tonight?
Shall we go to
the cinema?
8) Would
We use would
-
To make polite requests
Would you look
after my bag for a few minutes?
-
In conditional sentences
-
In reported speech as the reported form
of will
He said he would
help me, but he didn´t.
-
To talk about past habits
When we were
young we would sit on that old bench near the entrance to the park.
9) Should and ought to
We use should and ought to
-
To give advice
You should/ought
to be more careful about what you say in front of her, she repeats everything.
-
To say what we think is morally right.
Rich countries
should help developing countries.
-
To criticise a past action
You should have
made sure that tickets were in the bags.
You shouldn´t
have been so greedy.
We tend not to use oughtn´t to/oughtn´t to have as
it is too hard to say.
-
To make predictions based on previous
experience, or what is expected.
Don´t panic, there
should be another bus in a couple of minutes.
10) Need
We use need
-
To say when something is necessary or
unnecessary.
We need to
enroll everyone for the exam before the deadline.
We use needn´t to (don´t need) to say that something
is not necessary:
You needn´t buy/
don´t need to buy uniforms and equipment, everything is included in the fees.
ü
Remember
Need can be used both as a modal auxiliary, and as a
full verb with an auxiliary. This can be used to make an important distinction
of meaning in the past.
Need as a modal: I needn´t have worn a suit because everyone
was dressed casually = I wore a suit, but it wasn´t necessary.
Need as a full
verb:
I didn´t need to wear a suit, so I just
dresses casually like everyone else.
Need as a modal: I needn´t have bought the tools because the
company supplied everything = I bought the tools but it wasn´t necessary.
Need as a full
verb:
I didn´t need to buy any tools because
the company provided everything = it wasn´t necessary to buy any tools so I
didn´t.
