A1 a polite way of attracting someone's attention, especially of someone you do not know:

F0 used to politely ask someone to move so that you can walk past them:

F0 used to tell someone politely that you are leaving:

A2 used to say sorry for something you have done by accident:

F0 said before disagreeing with someone:

F0 _US (_UK pardon?, I beg your pardon?) used to politely ask someone to repeat something they have said because you have not heard it