1st July 2020

‘must’ or ‘have to’

‘have’ is a main verb, ‘must’ is a modal auxiliary verb

have can be followed by to + verb, and can be used in different tenses 

e.g. I have to go home

He has to do his homework

I had to write two reports (past tense)

‘must’ is an auxiliary verb so:

is followed by a main verb

is never used with ‘to’

I must exercise NOT I must to exercise

‘have to’

an obligation made by someone else

‘must’

an obligation made by yourself

I have to get a visa to enter China OR not allowed into China

I must do more exercise [This is MY choice, not forced.]

‘have to’

Sub + have to + infinite

POSITIVE: She has to try harder

NEGATIVE: He does not have to work tomorrow

QUESTION: Do you have to be so noisy ?

‘must’

Sub + must + base verb

I must sleep soon

You must go shopping

He must be nicer to his sister

Negative: Students must not (mustn’t) cheat in class

Question: Must we visit your family ?

Exercises: (answers at end of blog)

1. Yesterday I ________ finish my geography project.

 must
 mustn’t
 had to

2. She will ________ wait in line like everyone else.

 must
 have to
 has to

3. All employees ________ on time for work.

 must be
 mustn’t
 have to

4. We ________ forget to take the chicken out of the freezer.

 have to not
 must
 mustn’t

5. If you are under 13 you _____ to get your parents’ permission.

 have
 must
 musn’t

6. Your daughter may ________ try on a few different sizes.

 have to
 had to
 must

7. You _____ get here as soon as you can.

 must
 mustn’t
 have to

8. Do you _____ work next weekend?

 have to
 must
 mustn’t

9. Bicyclists _____ remember to signal when they turn.

 mustn’t
 must
 has to

10. Angela, you _____ leave your clothes all over the floor like this.

 mustn’t
 must
 have to

ANSWERS

1 had to // 2 had to // 3 must be // 4 mustn’t // 5 have // 6 have to // 7 must // 8 have to // 9 must // mustn’t //