This document discusses defining and non-defining relative clauses. It provides examples of defining relative clauses without commas and non-defining relative clauses with commas. It also discusses relative pronouns such as who, whom, whose, when and where and their uses referring to people, time and place. Finally, it addresses using prepositions in relative clauses.

1. Relative clauses
Defining relative clauses
The woman who showed the most determination
got the job.
We do not put commas at the beginning and end
of a defining relative clause.

2. Relative clauses
Defining relative clauses
She showed me photos of the gorillas (which/that)
she had studied.
She showed me photos of the gorillas which/that
lived nearby.
The letter (which/that) you received in September
explains our position.
The letter which/that arrived in September
explains our position.

3. Relative clauses
Non-defining relative clauses
Dian Fossey, who was born in the USA, made a
major contribution to the study of primates.
We use a comma before and immediately after
the clause.
We cannot omit the relative pronoun in nondefining relative clauses.

4. Relative pronouns
Which and That Things
The study that she published last month is
remarkable.
Her most recent study, which she’s just
published, is her best yet.

5. Relative pronouns
who
people
Dian, who has specialized in primates, has spent a
lot of time in Africa.
whom
people if they are the
object of the clause
Professor West, whom I worked with recently,
has won the Nobel prize.

6. Relative pronouns
whose
thing or people and expresses
possession or belonging
She is a scientist whose work is world famous.
The book, whose focus is African primates, is
very influential.

7. Relative pronouns
when
time
She described the moment when she first saw a
wild gorilla.
where
place
She spent many years in Africa, where she
observed gorillas in the wild.

8. Preposition in relative clauses
That was the story which the film was based on.
That was the story on which the film was based.

9. Preposition in relative clauses
That’s the research that/which she received the
award for.
That’s the research for which she received he
award.

10. Preposition in relative clauses
She spoke to a professor that/ who/ whom she is
friendly with.
She spoke to a professor with whom she is
friendly.