how we can distinguish clearly when we must use?. Thanks
I'm not sure that we can distinguish this clearly - in a way that is easy to explain. There are a large number of threads here that discuss the use of should, many about should and would. Have a look at these:how we can distinguish clearly when we must use?. Thanks
My mother says things like that a lot, and she isn’t posh at all! I don't think she'd use that specific sentence, but she might say, for example:But don't you British people sometimes say things on the order of, "If I were you, I should go to the beach!"