From my understanding, would and could are used in 3 main situations:
1. Hypothetical - If I could go shoppping, I would.
2. Polite requests - Would it be ok if you helped me?
3. Polite offers/invites - Would you like to get a drink?
When else are they used?
What is the difference between:
a) I advise you to buy a car.
b) I would advise you to buy a car.
To me, (b) could be half a type 2 conditional. If you asked me, I would advise you to buy a car. Anything else?
c) I don't see how I could possibly manage to do that.
d) I don't see how I can possibly manage to do that.
What effect does changing can to could have? Is it more polite? Does it show more doubt?