不说I will take your job until you get back. （取代）
而说I will fill in for you until you get back.
不说The general manager is not working at this moment. （眼下没在工作，待会会就回来了。）
不说The general manager is out of work. （失业了）
而说The general manager has got off work. 或sb has left for the day. 或者sb has clocked off.
I'm in the middle of something.
Cara do you want to join us for lunch?
Count me in./Sure thing./Yeah for sure.
Are you still up?
I will pay./It's on me./It's my treat.
Shall we order out?
I'm afraid that I'm going to be out sick today. I've got a nasty cold. I hope you don't mind.
I'm sorry I won't be able to come in today. I've come down with a bad cold.
He called in sick / He is off sick.