Bob and Bill wanted a drink, so they went back to the restaurant. This was not very clever, because Mr. Brown made them pay for their lunch.
Isn't that the Professor's hat? asked Mr. Brown. Oh, yes, said Bill. We're looking after it for him.
They had their drink, paid for it and left the restaurant, They were going back to see if Harry had finished the ladder.
Mr. Brown telephoned the Professor's house. Hello, wrong number speaking, said the Professor. I'm sorry, I mean this is Professor Brainyo. Mr. Brown told him about Bill and Bob and the hat.