I want to ask a question about using titles, but I think it is too broad to be asked here.
My question is this: under what circumstance and in what manner should you address Christian clergy?
Do you address them by their personal titles, such as mister, mistress, or miss? Do you address them by their professional titles, such as Doctor or Professor, if they happen to have a PhD degree in Theology? Do you address them by "Your Eminence" or "Your Reverence" or "Your Grace"? Or maybe all those titles apply to formal situations, so in informal situations, you simply refer to them by their personal names, even though you would never address a professor by his/her first name or last name without the "Professor" as a prefix?
I also wish to know how to address Buddhist and Taoist and Jewish and Muslim clergy.