Let’s look at CAN and COULD in 5 different steps:
1 ability
2 possibility
3 permission
4 request
5 offer
✳️CAN = present ability
• I can speak English very well.
• I have this ability.
• I can party all night, every night.
• I have this ability.
• I can make the world’s best tiramisu.
• I have this ability.
✳️COULD = past ability
• I could speak English very well.
• I had this past ability.
• I could party all night, every night.
• I had this past ability.
• When I was at uni, I could study for hours. Now I can’t.
• I had this past ability.
✳️CAN = present possibility
• England can be very expensive.
• This is possible.
• Be careful. The noodles in this restaurant can be very spicy even though I always say ‘No chili please!’.
• This is possible.
✳️COULD = possibility in general
• You can use ‘could‘ for the past, present or future. The context of the situation/ sentence will tell you if ‘could’ is referring to the past, present or future.
• My granddad could either be a very nice person, or he could be a horrible person. It always depended on the day.
• These are two past possibilities.
• If we don’t want to cook tonight, we could go out. What do you think?
• This is a future possibility.
✳️COULD HAVE + PAST PARTICIPLE
• We use ‘could have + past participle‘ when we are speaking about a past hypothetical situation. This is something that did NOT happen.
✳️CAN = informal permission
✳️COULD = formal permission
• Can I borrow your phone? (informal)
• Could I borrow your phone? (formal)
We only use CAN when we give permission. Not COULD.
✳️CAN = informal request
✳️COULD = polite request
(Both are polite if you use ‘please’, but CAN is more informal.)
• Can you close the window please? (informal)
• Could you close the window please? (more polite)
✳️POLITE OFFER – Can you help someone?
Use either CAN or COULD!
• I can/could drive you to the airport if you need me to.
• I can/could help you with your essay if you want.
