like to know what the difference is between must and have
should I use one and not the other?
have to and have got to: expressing the present
Must, have to and have got to are all used
to express obligation or theneed to do something.
They can be used interchangeably in the present tense, except that
must suggests that it is the speaker whohas decided
that something is necessary, whereas have to and have
got to suggest that somebody else has imposed the decision.
Have got to is characteristic of very informal speech. Have
to sounds slightly more formal.
must clean the house before mum gets back. I want her to
find it all neat and tidy.
I can't come out now. I've got to tidy up my room before
I'm allowed out.
has to attend the clinic every two weeks. He's really quite
must come and visit us again soon. It's ages since we saw
frequency adverbs such as always, often, sometimes,
never, etc, have to is normally preferred:
usuallyhave to work on Saturdays so I hardly ever
go away for the weekend.
sometimeshave to get their own suppers if their
mother is working late.
and have to: expressing
the future and the past
and have gotto have no future or past tense
cannot say:I had got to.../ I'll have got to.../
I'll must.../ I've must....
we can also use must to express future as well as
present intention, especially if it is the speaker who decides
that something is necessary. But it cannot be used to express
to is the only one of the three that possesses past and
Compare the following:
get to Leeds by ten, I shall have to leave London before
get to Leeds by ten, I must leave London before six tomorrow.
have to put the scaffolding up before you go on to the roof.
It's not safe otherwise.
have to have that tooth extracted. It's very badly infected.
had to leave the party early. Tom was obviously unwell.
had to cancel our holiday. Tom is just not well enough for
a walking holiday.
have to and have got to in the interrogative
to and have got to are often preferred in the interrogative,
especially if the obligation is imposed from the outside.
time have you got to be back? ~ Dinner's at seven. So by
half past six really.
often do you have to travel to America on business?
About once every six months.
you leave right now? Won't you stay a little longer?
you have to leave now? ~ I do, unfortunately. I've got to
collect my son from school.
to and mustn't
have to use have to for the negative of must
when there is no obligation or necessity to do something:
don't have to drink champagne at the reception. You can
have a soft drink.
didn't have to play after all. Jane turned up and could
won't have to drive Tom to the airport next Saturday. Julie's
use mustn't to say that something is not allowed
mustn't drink if you're going to drive afterwards.
mustn't drink that water. It's contaminated.
mustn't lie under oath. If you do, that's perjury.
mustn't forget my keys. I'll put them here so that I remember