A letter of invitation
Peter: Hello, Mary. Haven't seen you for a long time, How are you doing recently ?
Mary: I am fine, thank you.
Peter: Are you free this weekend ?
Mary: Sure.
Peter: I'd like to invite you to attend my birthday party this   Saturday evening.
Mary: Oh, it's cool! When does it start?
Peter: The party will be held at 7pm in my home, you can come any time between 6:30 and 7.  
Mary: But when does it finish?
Peter: It will last three hours, so it will finish around 10:00 ...