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Modal

( Free Online English Grammar Lessons )

Read time : 7 minutes

Advice

Form : ( Should / Shouldn't / Ought to / Oughtn't + infinitive with to )

In English we use should / shouldn't /ought to / oughtn't to give advice. We use should / ought to to say something is a good thing to do and shouldn't / oughtn't to say something is a bad thing to do.

Example sentences :

  • You ought to eat salad more often.
  • You shouldn't eat so many pizzas.
  • You should go to a gym twice a week.
  • You should try to lose some weight.
  • You shouldn't get too stressed at work.
  • You ought to exercise regularly. 
  • You should go to the doctor if you don't feel well tomorrow.
  • She ought to change jobs. 

Note : To ask for advice we can say: What should I do?


Ability / Possibility / Permission

Form : ( Can / Could / Be able to + infinitive without to )

In English, "can" is a modal verb and only has a present, past and conditional form. It can also be used with a future meaning. 

Example sentences :

  • I can play the piano very well.
  • Alice can't come tonight. She has a migraine.
  • Can I open the window?
  • It can get very hot in summer in Perth.
  • I can't speak English.
  • You can smoke in the garden. 

Note : Can is not used to talk about specific possibilities.

Example sentences :

  • Where are my keys? They could / may/ might be in the kitchen. NOT They can be in the kitchen.

In English, could is used to talk about past ability/ permission/ possibility.

Example sentences :

  • I could swim when I was five.
  • Could I open the window?
  • He could be running late. 
  • He could dance when he was young.
  • She could read when she was three years old.
  • Could I go to the toilet, please?
  • When I was a child I could only have dessert if I'd eaten my dinner.
  • Where is John? He could be working in the garden. 

"Be able to" can be used in the present, past, future, present perfect and as a gerund or infinitive.

Example sentences :

  • He has been able to speak English fluently since he returned from England.
  • I'd like to be able to cook Thai food.
  • Being able to sleep late is a luxury!

Note : be able to in the present and past is more formal than can or could.


Form : ( Might / May + infinitive without to )

In English we use might or may to say something in the future is possible, but not decided.


Example sentences :


  • I might go to the pub with Claire tonight.
  • She might bring some friends to the party.
  • He may take the day off work tomorrow.
  • You might like the movie.
  • We might go to the theatre on Saturday or we might go out for dinner.
  • They might stay with us when they visit London or they might stay in a hotel.
  • I might not watch the match tonight.
  • She mightn't come to the meeting.
  • We may not have a party next weekend.
  • May I go to the toilet?
  • Might I ask you a question? (formal)
  • It may/ might rain later.


To make questions with might we usually use Do you think...?


Example questions :


  • Do you think she might come to London this summer?
  • Do you think you might see Peter while you're in Perth?


In English we can also use might in short answers.


Example short answers :


  • Yes, she might.
  • No, I might not.


Obligation / Necessity / Prohibition

Form : ( Have to + infinitive without to )

In English we use have to + infinitive to say something is necessary or obligatory. We normally use have to for a general obligation from an outside source, such as work or the law.


Examples sentences :


  • I have to get up at 7am every day. (To get to work on time)
  • You have to drive on the left in the UK. (It's the law)
  • You have to wear a seatbelt in a car. (It's the law)
  • I have to go to a meeting tomorrow. (My boss says so)
  • I had to wear a uniform when I went to school. (It was the rule)


Form : ( Don't have to + infinitive without to)

In English we use don't have to + infinitive to say something is not necessary or obligatory. It means you can if you want to, but it's not necessary.


Example sentences :


  • He doesn't have to work on Sundays.
  • We don't have to wear a uniform at school.
  • You don't have to go swimming if you don't want to.
  • You don't have to pay for parking here. It's free. 


To make questions we use do/does.


Example questions :


  • Do I have to go?
  • Does he have to bring his CV?



Form : ( Must + infinitive without to )


In English we use must + infinitive to talk about rules and obligations. We normally use must when the speaker imposes the obligation, such as a teacher to students, or even to yourself.


  • You must turn off your mobile before boarding the plane. (because you are imposing the rule)
  • At this company you must work 40 hours a week. (because you are imposing the rule)
  • You must finish the assignment by Friday. (because you are imposing the rule)
  • I must lose some weight. (because you believe so)
  • I must buy a new shirt for my interview. (It's my own decision)
  • You must be on time for the test tomorrow. (Particular occasion)
  • I must go to the dentist about my toothache. (because you believe so)


Form : ( Mustn't + infinitive without to )


In English we use mustn't + infinitive to say something is prohibited.


Example sentences :


  • You mustn't smoke here.
  • You mustn't park here.
  • You mustn't drive down this street. It's one-way. (It's against the law)


Note : You can often use can't or be + not allowed to instead of mustn't.


Example sentences :


  • You can't smoke here.
  • You're not allowed to smoke here. (It's prohibited)
  • You can't speak loudly in a library.
  • You can't park here at rush hours during the week.


Note : Mustn't and don't have to have completely different meanings.


Mustn't Vs Don't Have To


  • You mustn't go. = You can't go. It's prohibited.
  • You don't have to go. = You can go if you want to, but it's not necessary.


Note : Have to is a normal verb and exists in all tenses whereas must is a modal verb and its only forms are must and mustn't.


You can also use have to and must for strong recommendations.


Example sentences :


  • You must go to Barcelona - it's amazing!
  • You have to visit Tate Modern while you're in London. 


Deduction

Form : ( Must / May/ Might / Can't + infinitive without to )

In English we use must when we are sure something is true.

Example sentences :

  • He has a big apartment in the city, a holiday house in Spain and he drives a Porsche. He must be rich!
  • The lights are on and his car's in the driveway. He must be home. 

In English we use may or might when we think something is possibly true.

Examples sentences :

  • He hasn't arrived yet. He might be lost.
  • She hasn't called me. She may not have my number.

In English we use can't when we are sure something is impossible.

Examples sentences :

  • He can't be ill. I saw him playing tennis this afternoon.
  • She can't be English. She has a foreign accent.
  • She can't be forty, she only looks thirty!

Note : In this context, the opposite of must is can't, NOT mustn't!


Past Modals

    Form : ( Modal Verb + have + past participle (Verb 3) )


In the past, can't, could, may, might and must for probability change to can't have, could have, may have, might have and must have + past participle (Verb 3).

  • He can't have seen us waving at him.
  • She could have had an accident.
  • She may have forgotten to phone him.
  • He might have broken a window.
  • She must have run to get here on time. 

  • In the past, should and ought to change to should have and ought to have + past participle (Verb 3).

  • You should have checked the train timetable before you left.
  • She shouldn't have carried so much cash in her bag.
  • They ought to have caught the robber by now.

    • Note : the form of "must" for obligation and "can" are exceptions.

      Must for obligation changes to had to + infinitive

  • He had to wear a uniform to school.

    • Can changes to could or was able to

  • I could play the piano as a child.
  • She was able to escape to safety.

Modal example sentences
I can't hear you, Mike!
I think they should be more understanding.
I don't like bank holidays, we still have to work tomorrow!
Can't you have the meeting another time?
By just paying a little bit more you could've rented a house in better condition.
Then we can talk, maybe!
Maybe you can teach me how to make phone calls.
I guess we should go and check another store.
We can ask the shop assistant first.
I don't know, she could do anything!
Can you please stop being stupid, dear?
Yes, sorry, I have to run!
Maybe we should start looking for houses in the suburbs first.
But I wonder what it says, can you show it to me, too?
We can get the other things on the way back.
I can smell something nice.
That's better, we can get some thighs.
Can you do me a favour in return?
I see, can you get a month long holiday from work?
Okay, I can make an appointment for you at 1 o'clock.


user profile picture preview
wasabi   1+ w
who the fuck uses ought to
Be going to
Be going to passive
Be used to / Get used to
Comparative
Defining relative clause
Echo tag
Expression
First conditional
Future
Future continuous
Future perfect continuous
Future perfect passive
Future perfect simple
Future simple passive
Greeting
Have/Get something done
Imperative
Implied conditional
Indirect question
Infinitive of purpose
Interjection
Mixed conditional
Modal
Modal passive
Non-defining relative clause
Other
Past continuous
Past continuous passive
Past perfect continuous
Past perfect passive
Past perfect simple
Past simple
Past simple passive
Polite request / offer / suggestion
Present continuous
Present continuous passive
Present perfect continuous
Present perfect passive
Present perfect simple
Present simple
Present simple passive
Question tag
Reduced relative clause
Reported speech imperative
Reported speech question
Reported speech request
Reported speech statement
Second conditional
Short answer
Superlative
Third conditional
Used to / would (past habit)
Was/were going to
Was/were supposed to
Wish
Would rather
Zero conditional