Grammar Focus

Must / Mustn’t / Have to

We use must, mustn’t and have to to talk about rules, obligations and things that are not allowed.

1. Must (πρέπει)

We use must for strong rules, duties, or when the speaker thinks something is very important.

Form: subject + must + base verb

• You must wear a helmet. → Πρέπει να φοράς κράνος.
• We must be quiet in the library. → Πρέπει να είμαστε ήσυχοι στη βιβλιοθήκη.
• I must finish my homework. → Πρέπει να τελειώσω την εργασία μου.

Careful: After must, use the base verb: She must go, not She must goes.

2. Mustn’t (δεν πρέπει / απαγορεύεται)

We use mustn’t when something is forbidden or not allowed.

Form: subject + mustn’t + base verb

• You mustn’t run in the classroom. → Δεν πρέπει να τρέχεις στην τάξη.
• You mustn’t touch the fire. → Δεν πρέπει να αγγίζεις τη φωτιά.
• We mustn’t be late. → Δεν πρέπει να αργήσουμε.

Important: mustn’t does not mean “δεν χρειάζεται”. It means “δεν πρέπει / απαγορεύεται”.

3. Have to / Has to (πρέπει / χρειάζεται να)

We use have to / has to for obligations, often because of a rule, schedule, or situation.

• We have to wear a uniform. → Πρέπει να φοράμε στολή.
• He has to do his homework. → Πρέπει να κάνει την εργασία του.
• They have to be at school at 8:15. → Πρέπει να είναι στο σχολείο στις 8:15.

4. Don’t have to / Doesn’t have to (δεν χρειάζεται να)

We use don’t have to / doesn’t have to when something is not necessary.

• You don’t have to come early. → Δεν χρειάζεται να έρθεις νωρίς.
• She doesn’t have to wear a uniform. → Δεν χρειάζεται να φοράει στολή.
• We don’t have to do this exercise. → Δεν χρειάζεται να κάνουμε αυτή την άσκηση.

Compare: You mustn’t run. = forbidden. / You don’t have to run. = it is not necessary.

5. Quick Comparison

6. Practice

A. Complete with must or mustn’t.

1. You __________ listen to your teacher.
2. You __________ run in the classroom.
3. You __________ brush your teeth every day.
4. You __________ touch dangerous animals.

B. Complete with have to / has to.

1. I __________ do my homework.
2. She __________ get up early.
3. They __________ wear school uniforms.
4. He __________ study for the test.

C. Choose the correct answer.

1. You mustn’t / don’t have to use your phone in the exam. It is forbidden.
2. You mustn’t / don’t have to bring food. We have food here.
3. She have to / has to clean her room.
4. We must / mustn’t cross the road carefully.

D. Write classroom rules.

1. You must __________________________.
2. You mustn’t __________________________.
3. We have to __________________________.