Hi, When do I use "can" or "could" Explain with examples - English - Tenses

Question

Hi,
When do I use "can" or "could"? Explain with
examples

Nitika Sahdev · Accepted Answer

'Could' is used to ask for permission: Could I
go to the classroom now?

'Can' expresses ability: I can swim under water
for a long time

Hi, When do I use "can" or "could"? Explain with examples.