Haben Sie Ihren Schlüssel? (do you have your key).
When is it appropriate to use deine or deinem. I thought deine or deinem might go there instead of ihren but I'm all confused
I know I've covered it somewhere in this program but I'm too lazy to look.

Hi Grant

You've got a couple of things to consider.  One is formal versus informal.  Dein is the informal possessive form just as Du is the informal form of you.  The next thing is the case which determines the ending.  There are charts somewhere in the lessons.  You can also browse on line and get grammar charts for all the pronouns and articles with appropriate endings for case.

In the example above, the usage is the formal Sie hence the possessive must correlate by using Ihr with the case appropriate ending.  Now if you were speaking informally the question would be 'Hast du deinen Schüssel?

Great thanks Byron, I'll do some delving and find some more on that later