I have seen and heard sentences like these: He could have gone too far. John can't have eaten all the cake. But I don't seem to encounter this structure: She can have done the work. I ...
Possible Duplicate: When do I use “can” or “could”? Is either “can” or “could” more polite? “Can” vs. “could” in asking a question “Can I have one apple from your box?” vs “Could I have one ...
Possible Duplicate: When do I use “can” or “could”? I was doing some reading on usage of can and could. I understand that can is used when asking for ability, and could for willingness. I ...
Possible Duplicate: When do I use “can” or “could”? I am a little bit confused about asking a question: Can you please tell me my next work? or Could you please tell me my next ...
Possible Duplicate: When do I use “can” or “could”? I wonder which of the following is more polite: Can you please change my email address? Could you please change my email ...
Most of the people says I wish I could, I wish you would. Can't we use I wish I can, I wish you will? I'd like to know what the main difference between the usage of can/will and could/would is.
When should I use can? When should I use could? What is right under what context?