ENGLISH GRAMMAR 2º (June, 1st)
MUST / HAVE TO
As you know, we use MUST to express obligation. However, we
can only use it in present, so How can we express obligation in other tenses
like past or future? To express obligation in the tenses that we cannot use
‘must’, we use the semi-modal HAVE TO + INFINITIVE (tener que). Nevertheless, it changes
according to the tense in which you are using it and it needs the help
of the auxiliaries to make the negative and the interrogative form.
For
example: I have to make the
exercises every day (present), I had to
make the exercises yesterday (past) or I
will have to make the exercises tomorrow.
Therefore, if the
sentence is in past or future, we can only use ‘have to + infinitive’ because
‘must’ can only happen in present. However, both MUST and HAVE TO can
occur in present, so What is the difference between them? Which one is the
correct option if the sentence is in present? We use must if the obligation is internal, that is the speaker puts the
rule.
For example, imagine
your mum tells you ‘You must be at home before 11 p.m’. We use ‘must’ because
your mother puts the rule or obligation.
If the obligation is
external , that is, the speaker does not put the rule but receives it , we use have to.
For
example : imagine the same situation, but now you are with your friends and you
tell them : ‘I have to be at home before 11 p.m’. We use ‘have to’ because you
(the speaker) haven’t put the rule ,
your mother did.
It’s
important that you remember that the third person singular form of ‘have to’ in
present is ‘has to’ and that use ‘does’ to make the negative and the
interrogative form.
1.-Copy the following chart in your notebook.
2.-Click on the link to practice using MUST and HAVE TO.
3.-Make exercises 1, 2 , 3, 4, 5 on page 65 and exercise 1 on page 66 in
your workbook to practice and review.
