General Revision Modal Verbs

What are modal verbs? Modals (also called modal verbs, modal auxiliary verbs, modal auxiliaries) are special verbs which are different from normal verbs like "work, play, visit...“ They give additional information about the function of the main verb that follows it.

Use of modal verbs: Express functions such as: Permission Ability Obligation Prohibition Lack of necessity Advice possibility probability

Modal verbs are followed by an infinitive without "to“: Examples: You must stop when the traffic lights turn red. You look awful! You should see a doctor. Exception: You ought to go to the doctor.

must must not can could may might Modal Verb Meaning Expressing Example must to have to 100 % obligation I must stop when the traffic lights turn red. to be very probable logical conclusion (deduction) He must be very tired after such enormous work must not not to be allowed to prohibition You must not smoke in the hospital. can to be able to ability I can swim to be allowed to permission Can I use your phone please? it is possible possibility Smoking can cause cancer ! could ability in the past When I was younger I could stay up all night and not get tired.. more polite permission Excuse me, could I just say something? It could rain tomorrow! may May I use your phone please? it is possible, probable possibility, probability It may rain tomorrow! might Might I use your phone please? weak possibility, probability I might come and visit you in America next year, if I can save enough money.

need need not should/ought to had better Modal Verb Meaning Expressing Example need necessary necessity Need I say more? need not not necessary lack of necessity/absence of obligation I need not buy any tomatoes. There are plenty in the fridge. should/ought to used to say or ask what is the correct or best thing to do 50 % obligation I should / ought to see a doctor. I have a terrible headache. to suggest an action or to show that it is necessary advice You should / ought to revise your lessons to be very probable logical conclusion (deduction) He should / ought to be very tired after such enormous work had better You 'd better revise your lessons

GOLDEN RULES ABOUT MODAL VERBS Modal verbs never add an -s in the third person singular:  He must work harder to pass his exams Modal verbs don’t need auxiliaries to make negative sentences or questions:  Should I apologise? I mustn´t smoke in hospitals Modal verbs only have one form. You need other verbs to express the same thing in the past, future etc. I´ve been able to finish on time.  

EXPRESSING ADVICE We use should and ought to to express advice or make recommendations: You should eat less fat if you want to lose weight. You ought to relax if you don´t want to get ill. You shouldn´t be rude to anybody. You oughtn´t to tell lies.  

EXPRESSING OBLIGATION OR NO OBLIGATION We use must and have to to express obligation. The difference between them is:  We use must when the obligation is inside the speaker. It is a moral obligation. We use have to when the obligation is outside the speaker. It comes from the situation.

EXPRESSING OBLIGATION OR NO OBLIGATION I must do some exercise to get fit. We have to be quiet in class. That’s the rule. Note: Have to is not a modal verb. We use don’t / doesn’t have to, needn’t and don’t /doesn’t need to to express no obligation. You don’t need to get up early. It is Sunday! She doesn’t need to wear a coat. It is warm outside. She needn’t cook tonight. We´re eating out.  

EXPRESSING PROHIBITION We use mustn’t to express prohibition. Children under 16 mustn’t go in there. At school we mustn’t smoke.