The meaning of must
is "The way I see/feel it in the present circumstances, it is necessary
to.." (The speaker feels/admits/endorses the idea of obligation).
Must expresses obligation of many different natures
obligation: You must pray and go to church.
as strong advice:
You must stop smoking, James.
in view of circumstances (obligation as necessity). We must slow
down, Tom: the police are behind us.
by law, from authority:
Minors must not be served alcoholic beverages.
obligation (deduction): You
must be the man who phoned yesterday night.
to expresses the
same range of obligations when they are not felt personally.
still expresses an obligation: a prohibition is after all, a negative
obligation, an obligation not to do something.
mustn't take sweets from strangers
Don't have to
expresses a lack of obligation: it's equivalent to Don't need to or Needn't.
There is no obligation.
You don't have to
brush your hair every ten minutes, darling.
modals of obligation
Can you express the idea of present obligation for a past fact? How can
you feel now that something is
compulsory, if it has happened already? It is impossible. . The only kind
of obligation that can be felt now about something past is logical
obligation (deduction) (the opposite is can't + perfect modal)
must have been very rich. è
the past, but the obligation is felt now.
You had to be rich(
if you wanted to mix with them).è
The idea of
obligation is past, as well as the circumstances.
You had to pray every
morning in that school. è
Again, a past
situation and a past obligation.
- The modals of possibility
(may, might, can, could) mean something like: "The way I
see/feel things in the present circumstances, it is possible that.."
For may and might, we should add: (..if I have anything to do with it).
- Could and might express remoteness of any kind (past time, unlikely occurrence,
stiffness -due to shyness or respect-.. )
- May and might express a more personal involvement in the creation of the
possibility (an extrictly personal opinion, or some kind of authority..)
are many kinds of possibility:
- Probability, chances: This could be your lucky day (It is likely,
- Theoretical possibility,
options: We can be friends, if you want to.
He can dance on his nose (He is able to..)
- Assumptions (logical possibility): This may well be the purse you lost
- Permission: Can I go to the cinema? –No, you may not. (You’re not
Their negative forms
use can’t to express that something is logically impossible
can’t be Julio Iglesias, with that awful watch!
meaning is kept in the perfect form:
can’t have broken your washing machine. She wasn’t here yesterday. (Talking about past facts, we consider them impossible now)
She couldn’t break your washing machine. (Remote action in time:
maybe she tried to break it but was not able to.) But we are not looking back
from NOW. It is just a past action.
modals of possibility
of the most common uses of perfect modals of possibility is for assumptions
about the past: we look back on an action that happened before, but we
consider it now. That is how we can discuss the possibility of past
facts now, or make regrets:
could have been a great opportunity. You could have been a bit more talkative!
It could be a terrific day for Man U.. (Now we think there is a
remote chance that it will be a terrific day) It could have been a
terrific day... (We now think that it was possible before that it
was a terrific day . We assume that it is impossible now).
might have been trapped in the mud. (We now think so)
might be trapped in the mud. (action now, possibility now as well)
might be the winners. (present winners)
might have been the winners. (we
think so now, but this sentence sometimes suggests they weren’t).
AND OBLIGATION Overhead Projector Transparency
to ponder -no answer provided-
What is the nature of this possibility?
cannot replace me.
What is the past of CAN?
cannot come today, but I could come tomorrow.
Who may say the following sentences?
I suggest the pudding?
I suggest the ostrich drumsticks?
Typical conversation between child and parent: (explain the reply)
I cross the puddle with my wellies and splash the car?
dear: you are so cute! No, you can, but you may not.
Can you see any difference between..
could be your lucky day.
might be your lucky day.
What's the difference between..
may not visit your boyfriend until he gets a proper job.
may find your glasses today. Don't lose heart.
Nature of the obligation in:
must be very patient with the children. Otherwise, you won't cope.
must be very patient with the children: they seem to adore you.
must be very patient with the children: their parents are watching you.
must be very patient with the children to get the job at the local nursery
must be very patient with the children. They don't mean to be a nuisance.
Apparently, Tommy caught the train yesterday. But, what kind of
obligation is conveyed? When is it felt?
had to catch the early train to Glasgow.
must have caught the early train to Glasgow.
Couple the sentences according to similarity in meaning (there is an odd
will have to read the instructions leaflet again.
has to read the instructions leaflet again.
can read the instructions leaflet again.
must read the instructions leaflet again.
should read the instructions leaflet again.