1. MODALS AUXILIARIES
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[DWS} Modals

2. Modal auxiliaries generally express speakers’ attitudes
Modal auxiliaries generally express speakers’ attitudes. For example, modals can express that a speaker feel something is necessary, advisable, permissible, possible, or probable; and, in addition they can convey the strength of those attitudes.
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3. Expressing Necessity: Must, Have to
All applicants must take an entrance exam.
All applicants have to take an entrance exam.
Explanation:
In example (a) and (b), it is neccessary for every applicant to take an entrance exam. There is no other choise. The exam is required.
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4. In everyday statements of necessity, have to is used more commonly than must. Must is usually stronger than have to and it indicate urgency or stress importance. (c) Sam has to talk to Jimmy right away. (d) Sam must talk to Jimmy right away.
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5. Expressing Lack of Necessity: Have to in negative
Tomorrow is a holiday. We don’t have to go to class.
I can hear you. You don’t have to shout.
In (a): it is not necessary for us to go to class tomorrow because it is holiday. In (b): ???
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6. Prohibition : Must in negative
Must not = prohibition ( DO NOT DO THIS)
You must not look in the closset. Your birthday present is hidden there.
You must not tell anyone my secret.
In (a): Do not look in the closet. I forbid it. Looking in the closet is prohibited. In (b): ???
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7. Expressing Advisability: Should, Ought to, Had better
You should study harder
You ought to study harder
Should and ought to have the same meaning: they express advisability.
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8. (c) You had better take care of that cut on your hand soon, or it will get infected. In meaning, had better is close to should/ought to, but had better is usually stronger. Often had better implies a warning of a treat of possible bad consequences. Had better is more common in speaking than writing.
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9. Expressing Ability: Can, Could
Tom is strong. He can lift that heavy bag.
Tom was strong. He could lift that heavy bag.
In (a): It shows the ability in the present and future time.
In (b): It shows the ability in the past time.
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10. Expressing Permision: Can, May
Yes, children. You may have cookies after dinner.
Ok, kids, you can have cookies after dinner.
(a) And (b) have the same meaning but may is more formal than can.
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11. Expressing Possibility: May, Might
It may rain tomorrow.
It might rain tomorrow.
(a) And (b) have the same meaning but might has stronger possibility than may.
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12. Expressing Logical Conclusion: Must
A: Nancy is yawning. B: She must be sleepy. Speaker B is making a logical guess . He bases his guess based on the information that Nancy is yawning. He uses must to express his logical conclusion.
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13. EXERCISES
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14. It's a hospital. You _____smoke.
He had been working for more than 11 hours. He _____ be tired after such hard work.
I _____ speak Arabic fluently when I was a child and we lived in Morocco. But after we moved back to Canada, I had very little exposure to the language and forgot almost everything I knew as a child. Now, I _____ just say a few things in the language.
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15. _____ you stand on your head for more than a minute? No, I _____.
The teacher said we _____ read this book for our own pleasure as it is optional.
_____ you stand on your head for more than a minute? No, I _____.
Take an umbrella. It _____ rain later.
You _____ leave small objects lying around. Such objects _____ be swallowed by children.
Drivers _____ stop when the traffic lights are red.
_____ I ask a question? Yes, of course.
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16. You _____ drive when you are so tired. It’s dangerous.
Adam has already eaten sandwhich and now he is making another one. He _____ be hungry.
You _____ drive when you are so tired. It’s dangerous.
I am going to be late. What _____ I do?
Sir, _____ I speak to Mrs. Black?
I do not know where Alicia is. She _____ be at home.
A fish _____ walk. But it _____ swim.
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