1. Сriticism
1.1. Present/future
1.1.1. You could at least help me
1.2. Past
1.2.1. You could have at least helped me last night
1.2.2. They should have tried harder. (but they didn't)
1.2.3. You ought to have behaved yourself yesterday. (It was the right thing to do but you didn't do it.)
2. Suggestions
2.1. Present /future
2.1.1. We could leave if you want.
2.1.2. /We can go now if you like.
2.1.3. Shall we dance?
3. Advice
3.1. Present/future
3.1.1. You should drink more water. (general advice; I advise you)
3.1.2. You ought to respect the elderly. (I advise you; most people believe this)
3.1.3. You had better finish it. it's a good idea; advice on a specific situation)
3.1.4. Shall I buy that car? (asking for advice)
3.2. Past
3.2.1. You should have gone to bed earlier last night. (but you didn't)
3.2.2. He ought to have seen a doctor earlier. (but he didn't)
3.2.3. It would have been better if you had finished it yesterday. (but you didn't)
4. Ability
4.1. Present/Future
4.1.1. He can read arabic
4.1.2. She is able to run a marathon
4.2. Past
4.2.1. He could/was able to read Arabic when he was four
4.2.1.1. (Repeated action, ability in the past)
4.2.2. He was able to escape
4.2.2.1. (Single action)
5. Prohibition
5.1. Present/future
5.1.1. You can't smoke there. (you aren't allowed to)
5.1.2. You mustn't smoke there. (it's forbidden)
5.1.3. You may not smoke there. (formal)
5.2. Past
5.2.1. They couldn't smoke there. (they weren't allowed)
6. Obligation
6.1. Present/future
6.1.1. We ought to help the poor. (It's the right thing to do, but people don't always do it.)
6.1.2. I have to go on a diet. (I'm obliged to; the doctor says so.)
6.1.3. I must go on a diet. (I'm obliged to; I say so.)
6.2. Past
6.2.1. I had to go on a diet a month ago.
7. Duty
7.1. Present/future
7.1.1. Everyone must obey the law.
7.1.2. People ought to be more tolerant.
7.2. Past
7.2.1. All the villagers had to obey the law.
7.2.2. He ought to have been more tolerant.
8. Requests
8.1. Present/future
8.1.1. Would you mind sending this fax? (polite)
8.1.2. Will you phone Jane tonight? (very friendly)
8.1.3. Might I use your phone? (very formal)
8.1.4. May I have a cup of coffee, please? (formal)
8.1.5. Could I borrow your book? (polite)
8.1.6. Can I borrow your book? (informal)
9. Offers
9.1. Present/future
9.1.1. Would you like me to help you?
9.1.2. Shall we do it for you? (informal)
9.1.3. Can I/we do anything for you? (informal)
10. Possibility/probability
10.1. Present/Future
10.1.1. 100% certanity
10.1.1.1. They will be home soon
10.1.2. <=90% certanity
10.1.2.1. He is likely to arrive tonight
10.1.2.2. It is likely that he arrives tonight
10.1.2.3. He can win the race
10.1.2.4. Greg should/ought to win easily
10.1.3. 50% certanity
10.1.3.1. They could/may still be at school
10.1.4. <=40% certanity
10.1.4.1. He might want some food
10.2. Past
10.2.1. <=90% certanity
10.2.1.1. It was likely that he had arrived the day befire
10.2.1.2. He was likely to have arrived the day before
10.2.1.3. He should have/ought to have arrived an hour ago
10.2.2. 50% certanity
10.2.2.1. He could have/may have spoken to Jenny yesterday
10.2.3. <=40% certanity
10.2.3.1. He might have forgotten
11. Logical assumptions
11.1. Present/Future
11.1.1. Positive
11.1.1.1. She must be working
11.1.2. Negative
11.1.2.1. She can't be working
11.1.2.2. She couldn't be at work
11.2. Past
11.2.1. Positive
11.2.1.1. She must have been working
11.2.2. Negative
11.2.2.1. She can't have be working
11.2.2.2. She couldn't have been at work
12. Permission
12.1. Present/Future
12.1.1. Allowing/Denying
12.1.1.1. You may use the phone
12.1.1.2. You can/can't borrow my car
12.1.1.3. You can't/mustn't see the patient
12.1.1.4. You may not be let inside
12.1.2. Asking for permission
12.1.2.1. Could I use your phone?
12.1.2.2. Might I speak to Mr. Jones?
12.2. Past
12.2.1. He wasn't allowed to/couldn't cross the border
12.2.2. He was allowed to cross the border
13. Necessity
13.1. Present/Future
13.1.1. I must buy a new jacket
13.1.1.1. (Necessity from the speaker)
13.1.2. I have to put some petrol in the car
13.1.2.1. (Necessity from the outside)
13.1.3. I've got to go to the bank now
13.1.4. My car needs repairing
13.1.5. My car needs to be repaired
13.1.6. They don't have to/don't need to/needn't come
13.1.7. I ought to get my hair cut
13.2. Past
13.2.1. I had to buy a new jacket
13.2.2. My car needed repairing
13.2.3. My car needed to be repaired
13.2.4. She didn't have to buy apples
13.2.5. She didn't need to buy apples
13.2.5.1. She bought apples
13.2.5.2. She didn't buy apples
13.2.6. She needn't have bought apples