Mr.White is at the Lost and Found. He's talking to one of the clerks there.

(W=Mr.White; C=clerk)
W: Excuse me. I couldn't find my luggage at the carousel.
C: OK. Come with me, please. See if you can find it in this room.
W: (after a while) It doesn't seem to be here.
C: In that case, do you have your baggage check stub with you?
W: Yes. Here you are.
C: OK. I'm afraid you'll have to fill out this form.
W: OK...(He looks at the form.) Hey! Wait a minute. How can I remember every item I have in the bag?
C: Why not? It's your luggage, isn't it? You should know what's in it.
W: Can you tell me everything you have in your pockets right now?
C: Uh...Um...OK, smart aleck! Just write down what you can remember.

Don't let the cat out of the bag.
doggie bag 食物袋
be slave to
carousel 行李輸送帶
while = time
just in case 以防萬一
Here you are. = Here you go. Here you are! 你在這兒！ Here we are.我們到了 或 找到了
jot down 略記