Al: Ben, I can't find my key to room 122
Ben: Oh
Al: I got into the classroom while you were leaving and probably put it on the desk just before you left. I only saw it was missing at the end of the class... can you check if you took both keys when you left the room?
Ben: Let me see
Al: Ok
Ben: Ouch, yeah, I just found your key in my pocket...
Al: That's ok, I'll just tell the janitor, they only have two keys
Ben: Ok, I'll be at the university tomorrow and will hand it back
Al: Ok, thanks
Ben: By the way, wanna drink a beer after work tomorrow? It's on me since all this trouble is my fault
Al: Fine for me! And we both made a mistake... but hey, if it's on you it's on you, haha!
Ben: Ok, see you tomorrow then
Al: Ok, bye
Al can't find a key to room 122. Ben accidentally took it. He'll bring it back to the university tomorrow.