Modal verbs for obligation are one of the functions of English modal verbs. This modal verbs for obligation lesson shows you how to use must and have to in English. You can find the exercises at the bottom of the page.
Must
Must is for simple present. It usually shows general obligations, like in these examples:
- Travellers must show their passport before boarding a plane.
- You must use a pencil on the test.
It is formal and normally used in writing. Notice how this example is formal:
- All employees must wear proper safety equipment.
Have to
Have to is not an actual modal verb, but it is used like a modal. You must conjugate the verb “have” depending on the time and subject.
- I have to work tomorrow.
- She has to work tomorrow.
It is used in all tenses.
- I had to work last night.
- She has had to work every day this week.
“Have to” is less formal than “Must”, so it is more common in conversation.
Must not and Don’t have to
“Must not” and “don’t have to” are completely different, but their meanings are often confused. “Must not” is a negative obligation and shows something that is prohibited, like in these examples:
- You must not eat in the computer room. (Food in the computer room is prohibited.)
“Don’t have to” shows something that is not necessary.
- I don’t have to work today. (Working is not necessary.)
Modal Verbs for Obligation Exercises
Now that you have learned about obligation with modal verbs, are you ready for some tests? Try these below:
Modal Verbs for Obligation Test
Modal Verbs for Obligation Test 2