Fill in the correct relative pronouns/adverbs. Write (D) for defining and (N) for non-defining. Add commas where necessary.

1. She had catoptrophobia, **which (N)** is the fear of mirrors, as a child. 2. Frank, **whose (N)** mum is a nurse, is afraid of needles. 3. This is the clinic **where (D)** he goes for treatment for his phobia. 4. It was after that plane crash last month **that (D)** he started to fear flying. 5. Rick, **who (N)** lives on the 20th floor, is afraid of heights. 6. Paul is my friend **who (D)** dad treats people with phobias. 7. Do you know the reason **why (D)** Tom didn't come to work?