MODAL VERBS an infinitive without to but not ought to do not take s in the third person do not use the auxiliary verb do / does / did

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1 MODAL VERBS Modal verbs are verbs with unique characteristics. They work with the main verb to add extra meaning to a sentence, for example, obligation or permission. Modal verbs share the following characteristics: We put an infinitive without to after most modal verbs (but not ought to) e.g. : I must go. You shouldn t swear. He ought to be more hard-working. Modal verbs do not take s in the third person. e.g. : She can drive. We do not use the auxiliary verb do / does / did with modal verbs to form negatives, questions or short answers. e.g. : I can t understand. She might not come.

2 ABILITY Present : can We use the modal verb can / can t to talk about present ability. e.g. : I can t swim very far now. Past : could / be able to We use could to talk about general ability in the past. e.g. : She could run very fast when se was young. We use the correct form of be + able to to talk about particular ability in the past (ability to do something on one occasion). e.g. : He injured his foot but he was able to continue playing. We can use the negative form couldn t to talk about general ability or particular ability in the past. e.g. : He couldn t talk until he was three. I couldn t find my cell phone yesterday. Other tenses : be able to e.g. : I haven t been able to go on holidays for years I won t be able to finish my homework tonight.

3 OBLIGATION Present obligation: must / have to We use must to talk about internal obligation. e.g. : You must obey your parents. We use have to (which is not a modal verb) to talk about external obligation. e.g. : You have to go up the stairs as the lift is out of order. Past obligation : had to We use had to to talk about a past obligation. e.g. : I had to fill in a form to apply for the job.

4 DEDUCTION We use must and can t to make logical deductions. Present deductions: must / can t. We use must when we are certain something is true. e.g. : He must be at home. The lights are on. We use can t when we believe or guess that something is impossible. e.g. : He can t be tired. He s been sitting all day long. Be careful! We do not use mustn t to make negative deductions. e.g. : He hates maths. He can t be solving maths problems. not He mustn t be solving maths problems. Past deductions : must have / can t have. We use must have + past participle to express a certainty or make a logical deduction about the past. e.g. : He was late for school this morning. He must have overslept. We use can t have + past participle to express an impossibility in the past. e.g. : He can t have passed his driving test. He s very sad.

5 POSSIBILITY Present : We use may (not) / might (not) / could (not) to talk about: present or future possibility e.g. : He may / might / could not pass the exam. Polite requests. e.g. : May I come in? Permission. e.g. : You may smoke if you want to. Past: We use may / might / could have + past participle: to express a possibility in the past. e.g. : I ve lost my cheque book. Someone may / might / could have stolen it. It s not very late. They may / might / could not have gone to bed yet.

6 ADVICE Present : we use should (not) / ought (not) to to give advice and make recommendations. e.g. : You should / ought to go to bed. You should /ought to tell the police. We use had better (not) + infinitive without to to give very strong advice or make threats. e.g. : You had better go or you ll be late. You had better not be late or you ll be grounded next weekend. Past : we use should / ought to + have + past participle to express regret about something. e.g. : I shouldn t have told him he is an idiot. to express criticism about past events. e.g. : He ought to have told us before.

7 LACK OF NECESSITY Present : needn t / don t have to (which is not a modal verb). We use needn t and don t have to when there is no obligation. e.g. : You needn t shout. I m not deaf. She doen t have to sit this exam if she doesn t want to. The modal verb need (without to), is only used in the negative and interrogative. In the affirmative we use need to to express necessity. e.g. : I need to work hard if I want to pass all my exams. Past : didn t need to / needn t have + past participle. We usually use didn t need to + infinitive to say that an action was not necessay. e.g. : He didn t need to do it. (= It wasn t necessary for him to do it. Perhaps he did it, perhaps he didn t) We usually use needn t have + past participle to say that an action was not necessary, but it happened anyway. e.g. : He needn t have done it. (= It wasn t necessary for him to do it, bu he did.)

8 PROHIBITION We use mustn t to talk about prohibition. e.g. : You mustn t disobey your parents. PERMISSION We use can( t) to talk about permission in the present. e.g. Can I open the window? We use be allowed to (which is not a modal verb) to talk about permission in other tenses. e.g. : He won t be allowed to watch this TV programme. They haven t been allowed to attend the lecture. We can also use could to talk about general permission in the past but not to talk about permission for a particular action. e.g. : I couldn t go out at night when I was a child. Last week, I wasn t allowed to go to a party as I was grounded. But not : Last week I couldn t go to a party as