modal verbs

CAN

should

have to

modal verbs

must

have to/must

What you already know and new informations

Let's practice!

CAN

CAN'T

-- negative: can+ not = cannot-- short: can't Not being able to do something. I can´t speak Spanish. We can´t go to the cinema today.

-- Can is used to express ability or to say that something is possible. I can speak Spanish. He can play football after school.

SHOULD

SHOULDN´T

-- To give advice, a recommendation or a suggestion This is to say that it is the right thing to do or the correct thing.I think you should study for the test so that you don't fail. -- Obligation that is not as strong as Must. Sounds more polite. You should never lie to your doctor.

--negative: should + not= should not --short: shouldn't-- We use shouldn't to advise not to do something, usually because it is bad or wrong to do. We shouldn't leave without saying goodbye.

HAVE TO

DON´T HAVE TO

-- negative: don't + have to = don't have to -- No obligation. I don't have to work on Sundays.

-- Strong obligation (possibly from outside) Children have to go to school.

MUST

MUSTN´T

-- To express obligation or duty This also refers to laws and regulationI must memorize all of these rules about modal verb.People must remain seated until the show is over.-- To emphasize the necessity of something. Humans must have drinking water at least every two days. You must give up smoking, it's bad for you.

-- negative: must + not = mustn't-- Prohibition You mustn't use your smartphone while you are driving.You must not open the gift until it is your birthday.

MUST/HAVE TO

Have to and must are used to express obligation. There is a slight difference in the way that they are used. Have to shows that the obligation comes from someone else, not the speaker. This is usually referring to a rule or law. - We have to be at the airport at least two hours before the flight. Must shows us that the obligation comes from the speaker. - I must buy a new laptop.

Have to is more informal while Must is mostly used in written orders or instructions.

Let's practice!

1. What can you do? Can you swim or play computer games after school? Give examples. 2.What are you obligated to do? 3.What do you think you should do? Is it better to Do your homework when you comeback home from school or in the evening? Give examples.