. * Fill in the correct relative pronouns/adverbs. Write
(D) for defining and (N) for non-defining. Add commas
where necessary.
1 She had catoptrophobia
... is the
fear of mirrors as a child.
2 Frank
mum is a nurse is afraid
of needles.
3 This is the clinic
he goes for
treatment for his phobia.
4 It was after that plane crash last month
he started to fear flying.
5 Rick
lives on the 20th floor is
afraid of heights.
5 Paul is my friend
dad treats
people with phobias.
- Do you know the reason
Tom
didn't come to work?
.

1. She had catoptrophobia, which is the fear of mirrors, as a child. (N)

Explanation: The phrase "which is the fear of mirrors" provides additional information about catoptrophobia. It is a non-defining relative clause because the information is not necessary to identify the noun "catoptrophobia". Commas are used to set off non-defining relative clauses.

2. Frank, whose mum is a nurse, is afraid of needles. (D)

Explanation: The relative pronoun "whose" introduces a defining relative clause that specifies which Frank is being referred to. The information about Frank's mum being a nurse is necessary to identify which Frank is being discussed.

3. This is the clinic where he goes for treatment for his phobia. (D)

Explanation: The relative pronoun "where" introduces a defining relative clause that specifies which clinic is being referred to. The information about the clinic being the place where he goes for treatment is necessary to identify the clinic.

4. It was after that plane crash last month that he started to fear flying. (D)

Explanation: The relative pronoun "that" introduces a defining relative clause that specifies when the fear of flying started. The information about the plane crash last month is necessary to identify the event that triggered the fear.

5. Rick, who lives on the 20th floor, is afraid of heights. (D)

Explanation: The relative pronoun "who" introduces a defining relative clause that specifies which Rick is being referred to. The information about Rick living on the 20th floor is necessary to identify which Rick is being discussed.

6. Paul is my friend, whose dad treats people with phobias. (D)

Explanation: The relative pronoun "whose" introduces a defining relative clause that specifies which Paul is being referred to. The information about Paul's dad treating people with phobias is necessary to identify which Paul is being discussed.

7. Do you know the reason why Tom didn't come to work? (D)

Explanation: The relative pronoun "why" introduces a defining relative clause that specifies the reason for Tom not coming to work. The information about the reason is necessary to identify why Tom didn't come to work. No commas are needed in this case.

Overall, relative pronouns (such as which, whose, where, that, who, why) are used to join relative clauses to the main clause. Defining relative clauses provide essential information to identify the noun they modify, while non-defining relative clauses provide additional, non-essential information. The use of commas depends on whether the relative clause is defining or non-defining.