A: Did you wipe your feet?
B: Yes, of course I wiped my feet.
A: Then why is there mud on the carpet?
B: I don't know. It's not my mud.
A: Well, someone brought it into the house.
B: Look at the bottom of my shoes. They're clean.
A: Of course they're clean. You left all the mud on the carpet.
B: Okay, I'll get the vacuum cleaner.
A: Don't vacuum it now.
B: Don't you want me to clean up the mud?
A: Wait till it dries. It will be easier to vacuum.
B: Next time I will be more careful.