—Do you know       ? —I’m not sure, maybe he is an artist.

---- May I smoke here?---- If you      , choose a seat in the smoking section

The boss ______ the worker how to do it, or the accident couldn’t have happened.

--The man in a black suit _______ be our youth worker.--- I’m sure it _______ be him. I saw him in the laboratory building some minutes ago.

A giant of a man was standing in the doorway. His face was almost completely hidden by a long and untidy hair and a wild beard, but you ______ make out his eyes, shining like black beetles under all the hair.