0 past simple of "can", used to talk about what someone or something was able or allowed to do: --
1 used as a more polite form of "can" when asking for permission: --
2 used as a more polite form of "can" when asking someone to provide something or do something: --
3 used to express possibility, especially slight or uncertain possibility: --
4 used for making a suggestion: --
5 used for saying, especially angrily, what you think someone else should do: --
I waited ages for you - you could have said that you weren't coming!
Well, you could try to look a little more enthusiastic!
I could look after Toby for you.
It is not inconceivable that she could be lying.
You could be the Queen of England, for all I care - you're not coming in here without a ticket.