The document outlines 5 rules for using relative pronouns in adjective clauses: 1) the relative pronoun cannot be omitted if it refers to the subject of the embedded sentence, 2) it can be omitted if it refers to an object, 3) use "whose" if it refers to a possessive, 4) use "where" if there is a preposition of place, and 5) use "when" if there is a preposition of time. Examples are provided to illustrate each rule.

1. S
Five Rules about
Embedded Sentences
in Adjective Clauses

2. Rule #1: The relative pronoun cannot be omitted if
it stands for the subject of the embedded
sentence.
One of my favorite movies is Close Encounters of the Third Kind, a
science fiction film which was made by Steven Spielberg in 1977.
Main
Sentence:
One of my favorite movies is Close Encounters of the
Third Kind, a science fiction film.
Embedded
Sentence:
This science fiction film was made by Steven
Spielberg in 1977.

3. Rule #2: The relative pronoun can be omitted if it
stands for an object in the embedded sentence.
One thing I like about this movie is the acting.
Main
Sentence:
One thing is the acting.
Embedded
Sentence:
I like one thing about this movie.

4. Rule #3: Use whose as the relative pronoun to
replace a possessive in the embedded sentence.
The main character is an ordinary man whose name is Roy
Main
Sentence:
The main character is an ordinary man.
Embedded
Sentence:
His name is Roy/

5. Rule #4: Use where as a relative pronoun when
there is a preposition of place in the embedded
sentence.
The movie has scenes that take place in a lot of different places in
different parts of the world where a team of scientists travel to
investigate messages from a spaceship.
Main
Sentence:
The movie has scenes that take place in a lot of
different places in different parts of the world.
Embedded
Sentence:
A team of scientists travel to different parts of the
world to investigate messages from a spaceship.

6. Rule #5: Use when as a relative pronoun when
there is a preposition of time in the embedded
sentence.
In the end, when the spaceship finally lands on a mesa in Colorado,
it turns out that the visitors from outer space are friendly
ambassadors.
Main
Sentence:
In the end, it turns out that the visitors from outer
space are friendly ambassadors.
Embedded
Sentence:
At that time, the spaceship finally lands on a mesa in
Colorado.