Can, could and may are used when asking for permission but might is not.
May is the politest; could is second in line and can comes in last.
We only use may in first person singular and third person plural when asking for permission.
Example
May I open the window please?
May we open the window please?
May you/he/she/they open the window?
However, when giving permission or directives, we can also use may in all persons except for first person singular for obvious reasons.
You may go now.
You may be seated. (This is used in very formal English, such as in church, in a court of law or at a conference).
Others uses of the above directive take a shift in meaning to possibility. That is why context is of extreme importance.
Example
You may be seated next to John’s brother at the wedding (there is the possibility that your seat will be next to John’s brother)
May can also be used to express a fact.
I may be poor but I am happy = Even though I am poor, I am happy.
May is also used to express your best wishes to people.
May you have a happy and prosperous 2017 ( A new year’s wish)
May you have a great birthday. (A birthday wish on a birthday greeting’s card)
May you live a long and happy life together. (Wedding wishes to the bride and groom)
Can and could, unlike may, are used in all persons.
When asking for permission in the future, may and can and could remain unchanged.
CAN VERSUS ALLOWED TO FOR PERMISSION
Asking for permission to do something
Can I make a telephone call?
Could I make a telephone call?
I can go out in the evening. (I have the permission from my parents – this is always true, not just on a single occasion)
I am allowed go out in the evening (This is the same as the above example – I have the permission from my parents)
I can go to the party next Saturday. (Future permission)
Careful!
I could go to the party last Saturday. Can does not become could for past permission in the affirmative.
However, in the negative, couldn’t, is possible for lack of permission.
I couldn’t go to the party last week. (Ambiguous without context) To make the meaning clearer it is better to say: “I wasn’t allowed to go to the party last week,” or “My mother wouldn’t let me go to the party last week.”
However, we understand if the speaker refers to lack of permission if a context is given.
Example
I couldn’t go to the party last week because my mother wouldn’t let me.
(She did not give me the permission to go) For a single past action use be allowed to
I was allowed to go to the party last Saturday. (My parents gave me their permission on that occasion)
CAN AND COULD FOR REQUESTS, OFFERS, SUGGESTIONS AND
We use can in less formal situations when making requests and could in more formal situations. Could is a politer version of can.
Examples
Can you help me move the sofa please? (Making a request)
Could you ask Mr Jones to call me back please? (Making a more formal request)
We can/could meet outside the cinema if you like? (A suggestion – indicating this is a possibility)
Person A: “Tomorrow’s a holiday so what would you like to do?”
Person B: “We could go to the museum tomorrow if you like. I read on internet that entry is free just for tomorrow.” (A suggestion/recommendation)
Can I help you with that heavy bag? (Offering assistance) EXERCISE TEN
What is the meaning of ‘could’ in the following examples?
Which of the following meanings belongs to each example?
AP for permission D for deduction I for inability
MS for making a suggestion O for offer
PR for polite requests
1. At the airport: Passenger to assistant: Could I have a window seat please?
2. “What nationality is Sandra?” “She could be Italian. She’s got that Mediterranean look.”
3. Could you please put out your cigarette? You can’t smoke in here. It’s a no-smoking zone.
4. I couldn’t speak English until I was forty years old. I sorely regret not learning sooner. But as the saying goes, it’s better late than never.
5. Could I have a look at that newspaper please?
6. She couldn’t come to the party because she was laid up in bed with the flu. What a pity! She would have loved it.
7. We’re going to the park. You could come too if you’re free.
8. Eating a lot of fatty foods could raise your levels of cholesterol.
9. Could you come this way please? Mr Adams will be with you in a moment.
10. I could be late in getting home tonight but I’ll let you know for sure later on this afternoon.
11. Person A: “Could she be John’s sister? What do you think? She looks awfully like him.”
Person B: “She could be. Who knows?”
12. We could dine out tonight if you like?
13. We could meet at 7p.m.
14. Could we see the menu please?
15. I couldn’t see the road ahead of me because of the thick fog.
16. We could ask dad and see what he says.
17. The dentist could see you tomorrow at 11 a.m. That’s the only available appointment until next week I’m afraid.
18. I could see mum through the window as she struggled to open the garden gate.
19. Secretary to boss: “Could I take the day off tomorrow? I need to take my daughter to the doctor’s.”
20. On the phone to the bank: Good morning. How could I help you?
CHECK YOUR ANSWERS/EXERCISE TEN
2. “What nationality is Sandra?” “She could be Italian. She’s got that Mediterranean look.” D (Deduction/it’s a possibility)
3. Could you please put out your cigarette? You can’t smoke in here. It’s a no-smoking zone. PR (Polite request) 4. I couldn’t speak English until I was forty years old. I sorely regret not learning sooner. But as the saying goes, it’s better late than never. I (Inability)
5. Could I have a look at that newspaper please? AP (Asking for permission)
6. She couldn’t come to the party because she was laid up in bed with the flu. What a pity! She would have loved it. I (Inability)
7. We’re going to the park. You could come too if you’re free. P (Possibility) 8. Eating a lot of fatty foods could raise your levels of cholesterol. P (Possibility)
9. Could you come this way please? Mr Adams will be with you in a moment. PR (Polite request)
10. I could be late in getting home tonight but I’ll let you know for sure later on this afternoon. P (Possibility) 11. Person A: “Could she be John’s sister? What do you think? She looks awfully like him.” P (Possibility) Person B: “She could be. Who knows?” P (Possibility)
12. We could dine out tonight if you like? MS (Making a suggestion) 13. We could meet at 7p.m. MS (Making a suggestion)
14. Could we see the menu please? PR (Polite request)
15. I couldn’t see the road ahead of me because of the thick fog. I (Inability) 16. We could ask dad and see what he says. MS (Making a suggestion)
17. The dentist could see you tomorrow at 11 a.m. That’s the only available appointment until next week I’m afraid. P (Possibility)
18. I could see mum through the window as she struggled to open the garden gate. A (Ability in the past)
19. Secretary to boss: “Could I take the day off tomorrow? I need to take my daughter to the doctor’s.” AP (Asking for permission)
20. On the phone to the bank: Good morning. How could I help you? O (Offering assistance/help)
Now think about which of the above examples of could sound natural when replaced with can then check your answers below.
Answers
1, 3, 5, 7, 8, 9, 17, 19 and 20
12, 13 and 16 (making a suggestion) sound more natural with could
although it is not uncommon to hear the use of can when making suggestions.
Could is the better choice in 19 and 20 as it is a politer form of can.