Very roughly: "а" is used to introduce a new or different meanings, "и" is used for the enumeration of the similar objects, "но" is used to describe limitations. Mostly.[/QUOTE]

After reading through this forum I came across this topic. Could you give me a few sentences with "а", "и" and "но" + some explanations? Actually I don't know what you mean by nor "limitations" nor "new or different meanings".