MODALS OF OBLIGATIONMODAL VERBS

What are MODAL VERBS?

• HE MUST TOMORROW

• They are auxiliary verbs, they go with other verbs

What are MODAL VERBS?

• HE CAN WILL MEET YOU

• 2 modals verbs cannot go together

• HE MUST TO MEET YOU TOMORROW

• Followed by infinitive without “to”, except modal verb HAVE TO.

What are MODAL VERBS?

• HE CANS MEET YOU

• Don’t have 3rd person “-s”

• LAST YEAR I CANNED

• Don’t have endings like -ed, -ing, etc

MUST & HAVE TO

• I must finish my homework before 8

• We have to start work at 9 am

They are both used to express that something is necessary

MUST

• I must find a hotel to stay at tonight

• The speaker decides that something is necessary (INTERNAL decision)

HAVE TO

• I have to wear a uniform

• Somebody else has made the decision, it’s not the speaker’s opinion (EXTERNAL decision)

OTHER TENSES

• MUST: past & future with HAVE TO

• When I was young, we had to wear a uniform at school

• Next year you will have to study harder

MUSTN’T & DON’T HAVE TO

• Very different meanings in negative:

• You mustn’t open the door

• You don’t have to open the door

MUSTN’T

• You mustn’t open the door. Lately there have been many robberies in the neighbourhood.

• (It’s forbidden /prohibited)

• =can’t/be not allowed to

DON’T HAVE TO

• You don’t have to open the door. I have the keys.

• (It’s not necessary)

SHOULD / SHOULDN’T• I think you should see the doctor

• I think you shouldn’t watch so much TV

• =ought to/ought not to

• Give an opinion about what’s the best thing do do.

• Not as strong as MUST /HAVE TO:

• You must see the doctor

• You have to see the doctor (You have no alternative, strong recommendation)