The modal verb
УHave ToФ differs from the others in that it is not defective
It can have the category of person and number and all tense-aspect forms
as well as verbals. It is followed by УTO-InfinitiveФ
We had to look all over the town
before we found what we wanted.
She will not have to wait for you.
УHave ToТ
builds up its interrogative and negative forms with the help of the
auxiliary verb УTo DoФ.
Do you have to work hard?
He doesnТt have to do what she tells
him.
It is used to express:
- Obligation or necessity arising out of
some circumstances .It is similar to its meaning with СMustФ
She is usually short of time so she
has to go by air.
In the past tense УHave toФ
indicates a fulfilled obligation
We had to do a lot of things so we
stayed in the country/we obliged and did it/.
УHave to У replaces УMustФ when
УMustФ cannot be used:
- To express past necessity or
obligation
We had to do it again.
- To express absence of necessity since
ТMUSTТ + not means prohibition
Compare:
You must not do it/Prohibition/
You donТt have to make another copy
of the document. This one will be enough/in the sense of
ФNeednТtФ/.
- To express future obligation .The
future of УHave ToФ makes toe obligation more precise.
YouТll have to take a taxi if you
want to catch a train.
