In Modals^x, Invitations^x

Hi,How could a person use the modal "would" correctly? I think the uses of it can be said to be in the categories of "request", "invitation", "conditional" and others. What I have most trouble is the conditional use of the modal "would". Would you...

I don't see a great deal of difference between a request and an invitation -- none that could be communicated entirely by a modal verb, at least. The difference seems to lie in what you expect the addressee to do.Request:. CJ

I've been told that must/have to are used interchangeably. However, my English text books say that the difference is some context considerable. What is your view on this? I don't know of any context in which the difference might be described as considerable. Perhaps you should post some...

Lcchang wrote:It seems to me that a present auxiliary "may" is used for the past event. That has confused me for a while. She may have forgotten our invitation. Other than being used for degrees of certainty for the events that was happened in the past, can "may" also be used for opinions and...

Dear teachers, I would lile to ask you some big questions, and please be any help. I read in my text book about the use of past modals for degrees of certainty and opinions and advice. For degress of certainty, the book says: Probability: She must have left already. She must not have...