In the United States and Canada，people often invite friends over for a meal，a party，or just coffee．

　　Here are the kinds of things people always say．"Would you like to come over for dinner tonight？""Hey，we're having a party on Friday．Can you come？To reply to an invitation，either say thank you and accept（接受），or say sorry and give an excuse（藉口）．Sometimes，however（但是），what people say is like invitations but which are not real invitations．For example："Please come over for a drink sometime．""Let's get together for lunch soon．"They are not real invitations because they don't talk about the date or time．They just show that the person is trying to be friendly．To reply to this，people just say"Sure，that would be great．"or"OK，thank you．"So next time you hear what is like an invitation，listen carefully．Is it a real invitation or is the person just being friendly？

　　根据短文内容回答问题。

　　1．Do people in the US often invite friends to dinner？

　　2．If you get an invitation，what would you say first？

　　3．Is it a real invitation，when people say"Come over for a coffee sometime，please．

　　4．Why do people say this if they don't really want to invite their friends to come？