Can is about a possibility or capability.
- Using can in the Present tense
- In the Past tense
- With Modals
Use can to express general capabilities.
I can run 100 metres in 1 minute!
Can and able to are the same in the present tense.
I am able to run 100 metres in 1 minute!
Could shows a possibility but usually with a condition.
I could run 100 metres in 1 minute … if I wanted to.
I can take you home, no problem!
Well, I could take you home, but you will have to pay for petrol.
Well I could challenge them, but I need to go shopping, so I hope they’re still here when I get back…
I can → I could
I can see the mountains → I could see the mountains
BUT this does not mean the action was done. It is a possibility in the past.
In my hotel room, I could see the mountains.
I am able to → I was able to
It was a possibility in the past BUT this means the action was done.
I ran like hell and I was able to catch the bus.
My trip to Switzerland was very busy but I was able to visit the moutains.
Modals change the meaning of the verbs.
I might go to the tournament
I should learn that technique
I have to practice more
To add “possibility”, do not use can. We use “be able to”
X: I might can → I might can help you
O: I might be able to → I might be able to help you
X: I should can learn that technique
O: I should be able to learn that technique
X: I have to can practice more
O: I have to be able to practice more