This is Bob. He's _____ doctor. a. a b. an Peter is ____ engineer. a. a b. an That's Oliver. He's ___ travel agent. a. a b. an Leonardo di Caprio is ___ actor. a. a b. an Fred is ____ electrician. a. a b. an Mr. Smith is ___ teacher. a. a b. an This is Gloria. She's ___ homemaker. a. a b. an That's John. H...