Specific situations and special occasions

You will know many of these expressions but may not be sure exactly how they are used.
1. Greeting: "Hello"
   Hi/Hello. How are you?
   Good morning, good afternoon, good evening
   How do you do
   Nice to meet you.
   How's it going? _ Not bad. How about you.

2. Farewells: "goodbye"
   Goodnight
   Bye, See you later/soon
   Have a nice weekend
   Nice to meet you

3. Happy occasions and celebrations:
   Happy birthday
   Happy/Merry Christmas
   Happy new year
   Congratulations

4. Special conventions
   Excuse me
   Sorry
   Cheers
   Good luck
   Bless you. (to S.O when they sneeze)

What could you say in these situations?
You are in a meeting. S.O enters the room and says you have an important telephone call. What do you say as you leave?
_ Excuse me for one moment.
Someone says somethings to you but you didn't hear all of it. What do you say?
Yoe met a new business client for the first time fifteen minutes ago, and now you are leaving. What do you say?
You are in a crowded bus. It is your stop you want to get off. What do you say to other passengers as you move past them?
You are staying with some English friends. What do you say to them when you leave the room in the evening to go to bed?
You are in the street. A woman walks past you and at the same time somethings fall out of her bag. She has her back to you. What do you say?
_ Excuse me, I think you've dropped something.
A friend tells you they have just won a competition.
Another friend is going for a job interview this afternoon.