MODAL VERBS

Modal Verbs

English Grammar

Index

1. Expressing ability

2. Expressing certainty and possibility

3. Expressing obligation and necessity

4. Expressing prohibition

5. Expressing permission and advice

• They are used to express the speaker's view of ability, certainty, possibility, obligation, prohibition and permission
• They always have the same form, this is, they do not take -s in 3rd person singular nor -ed in past

What are modal verbs characterised for?

Ability

Examples

• Liz can speak four languages, but she can't speak Russian.
• The doctor will be able to see you tomorrow.
• When I was a child, I could swim backwards.
• My bike's brakes were broken but I managed to fix them.

1. Can: used in present and future tenses
2. Can't: used in negative
3. Could: used in past tense
4. Be able to: used in all tenses. More formal.
5. Manage(d) to: can be used instead of was/were able to

Certainty and possibility

Examples

• She has starred over fifty films so she must be very well known.
• You can't be tired. You just got out of bed!
• You are wearing a Dior gown! You must have spent thousands of pounds on it.
• She can't have left her glasses at home- I saw her wearing them on the bus.
• I may come and visit you next summer.
• Sally is never late. She might have overslept.

1. Must: used for present. There is a good reason to say that this is certain.
2. Can't/couldn't: used for the negative
3. Must+ Have + Past Participle: certainty about the past
4. Can't/couldn't + Have + Past Participle: certainty about the past in negative
5. May/might/could: possibility about the present or future
6. May/might/could + Have + Past Participle: possibility about the past

Obligation and necessity

2. Necessity

1. Need to: used in all tenses

E.g. I need to restore the fridge so I'll go to the supermarket later.

1.Obligation

1. Must: external obligation, strong advices, goals and obligations that we establish for ourselves. Used in present tense
2. Have to: obligations that come from someone else. Often used in questions. Used in all tenses.

E.g The library is a silent space. You must keep quiet. My teacher has given me homework which I have to hand in next Monday.

3. No obligation/no necessity

1. Don't have to: lack of obligation. Used in all tenses.
2. Don't need to: lack of necessity. Used in all tenses.

E.g. You don't have to hand in the task this week, you can do it next one. We don't need to hurry. There's plenty of time.

Prohibition

Examples

• You can't go inside-it says 'No entry'
• You mustn't smoke inside.
• My sister doesn't let me use her CDs.
• We are not allowed to enter that pub because we are under 21.
• My parents didn't allow me to play computer games when I was a child.

1. Can't: used when something is prohibited
2. Mustn't: used when something is prohibited, dangerous or wrong.
3. Not let: used when someone does not allow someone else to do something.
4. (Be) not allowed to: passive form. External prohibition.
5. Don't allow someone to

2.Advice

Permission and advice

1. Should
2. Shouldn't: used in negative
3. Ought to
4. Ought not to: used in negative

1.Permission

1. Can
2. Could: used in past tense
3. Let
4. Be allowed to
5. May: used in formal situations

Examples

• You can/could use your phone during the break, not in class.
• Are we allowed to use the calculator in the exam?
• She let me use her bicycle to get to the station.
• You may leave the room when you have answered all questions.
• You should/ought to study more if you want to pass your exam.
• He shouldn't/oughtn't to smoke so heavily.