Relative clauses give more information about a subject or object. They usually follow and "agree" with the noun they modify and often occur between a Subject and Verb. However, they usually have no effect on the S - V relationship.
The man who works at IBM comes from Hong Kong.
The house that Jack built remains empty.

The people who came to the party had a great time.

Those who arrive early are entitled to a rebate.

I ate an apple that had a worm in it.

She is the one who I told you about.

The man who lives over there is my uncle.

One of the men who lives over there is my uncle.

Only one of the people who work in the company is qualified.

Most relative clauses use the words who, whom, whose, which, that, when or where.

This is the place where I met my wife.
Paul is the man who loves Mary.
Simon is the man who(m) Mary loves.
(subject position)
(object position)

Commas which set off relative clauses function like parentheses ( ) indicating non-essential information.

My wife, who is a doctor, works at Community Hospital.
My wife (who is a doctor) works at Community Hospital.

Without commas, relative clauses specify one member of a group:

My brother who is a scientist works at the university.
My brother who is a mechanic works at Bob's Garage.

Specifies "which brother" (one of many)

You may delete the relative p___oun and the be verb when:

1. they are followed by a prepositional phrase.

A. The man who is in the house is my father.
The man in the house is my father.

B. The books that are on the desk are mine

The books on the desk are mine.

2. the main verb in the relative clause is progressive.

A. The man who is swimming in the lake is my father.
The man swimming in the lake is my father.

B. The books that are lying on the floor are mine.

The books lying on the floor are mine.

You may NOT delete the relative p___oun and the be verb when :

1. they are followed by an adjective:
The man who is angry is my father

X The man angry is my father

(However, you may switch the positions of the adjective and noun.)

The angry man is my father. (okay)

2. they are followed by a noun:

The man who is a doctor is my father.

X The man a doctor is my father.

The relative p___oun can be deleted if there is a new subject and verb following it:

A. This is the house that Jack built.
B. This is the house Jack built.
A. The person whom you see is my father.
B. The person you see is my father.

A. This is the place where I live.
B. This is the place I live.

A. I don't know the reason why she is late.
B. I don't know the reason she is late

(Also : I don't know why she is late. )

A. The woman whom he likes is married.
B. The woman he likes is married.

Notes:

Do not delete a relative p___oun that is followed by a verb other than be:

The man who likes lasagna is my father.

X The man likes lasagna is my father.

Never delete the relative p___oun whose:

The man whose car broke down went to the station.

X The man car broke down went to the station.

See also:
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