5. Relative Clause / Adjective Clause

A relative clause known also as an adjective clause is a subordinate (dependent) clause, and is therefore never a complete statement. It gives additional information about the noun, which can be someone or something, in the main clause. The relative or adjective clause can function as an adjective, a subject, a direct object, or an object of a preposition.

The position of the relative clause is immediately after the noun in the main clause and is introduced by a relative pronoun which is one of the following: that, which, who, whom, and whose. Two relative pronouns who and whom are used to refer to people, while which is used to refer to things. When referring to people and things, both that and whose can be used. The relative pronoun is usually the subject or object of a verb in the relative clause. Other pronouns that can start a relative clause include what, when, whatever, whichever, whoever, whomever, whichsoever, whosoever, whomsoever, whosesoever, and whatsoever.

Examples:

My old uncle is a bachelor.
(Let us have additional information about my old uncle.)
My old uncle is a bachelor. He showed me a photo of his new girlfriend.
(We can now use a relative pronoun [who] to change the second sentence into a relative clause by replacing the pronoun he with the relative pronoun. The relative clause is then combined with the first sentence.)
My old uncle who showed me a photo of his new girlfriend is a bachelor.
(The relative pronoun always replaces a noun or pronoun. Here, the relative pronoun who is used to replace the pronoun he to form a dependent or adjective clause. The first sentence my old uncle is a bachelor becomes the main clause. Pronouns who and that are used for people. Uncle is a person, so who is used.)

A relative clause is also introduced by an adverb called a relative adverb. The relative pronouns act as relative adverbs are where, when and why.

Examples:

Security forces raided the rebels’ hideouts where they recovered a huge quantity of arms and ammunitions.
I was in the shower when the explosion in a nearby factory occurred.
There must be some reason why the whales became stranded on the beach.

Functions of a relative clause

As subject:

Examples:

That was the new driver who drove his bus into a lamppost.
There are many restaurants here that also serve vegetarian food.
These large chunks which came from space are called meteorites.
The woman, whose husband is a prisoner, is herself an ex-prisoner.

As direct object:

Examples:

The vulture is one bird that I dislike.
She is my distant aunty whom I know nothing about.
These are the crabs which we have caught.
The woman, whose child we look after, is a prisoner.

As object of preposition:

When a preposition is used in a relative clause, the relative pronoun can be the object of the preposition. The preposition can appear either at the beginning of the relative clause; that is, in front of the relative pronoun and is called the object of preposition, or at the end of the clause.

Examples:

This is the house, for which he paid a million dollars.
This is the house, which he paid a million dollars for.

That is the roller coaster, on which we rode for hours.
That is the roller coaster, which we rode on for hours.

In that cottage lived my uncle with whom we sometimes stayed for a month.
In that cottage lived my uncle whom we stayed with sometimes for a month.

When the preposition is at the end of a relative clause, we can replace which and whom with that.

Examples:

This is the house, for which he paid a million dollars.
This is the house that he paid a million dollars for.

That is the roller coaster, on which we rode.
That is the roller coaster that we rode on.

In that cottage lived my uncle with whom we sometimes stayed for a month.
In that cottage lived my uncle that we sometiems stayed with for a month.

Whether a relative pronoun in a relative clause acts as a subject or object of the clause, another pronoun should not be added as the subject or object.

Examples:

Incorrect: There are many ducks that they swim on the village pond.
Correct: There are many ducks that swim on the village pond.
(The word that is the subject of the relative clause. Introducing the personal pronoun they as another subject is therefore unnecessary.)

Incorrect: This is the hotel which we stayed in it on one of our regular visits.
Correct: This is the hotel which we stayed in on one of our regular visits.
(The word which is the object of the relative clause. It is therefore not necessary to have the personal pronoun it as another object.)

Omission of relative pronoun acting as subject.

A relative pronoun cannot be omitted when it is the subject of the relative clause.

Examples:

The tooth that caused him toothache the whole night has been extracted.
Not: The tooth caused him toothache the whole night has been extracted. .
The fire, which burnt down the row of wooden houses, was started from a cigarette butt.
Not: The fire burnt down the row of wooden houses was started from a cigarette butt.

Omission of relative pronoun acting as object.

Relative pronouns may be omitted when they are objects in relative clauses.

Examples:

The one thousand dollars which he won in a lottery lasted only a week.
The one thousand dollars he won in a lottery lasted only a week.

My only friend whom I have trusted disappeared with my car.
My only friend I have trusted disappeared with my car.

My pet rabbit that I bought yesterday died this morning.
My pet rabbit I bought yesterday died this morning.

Relative pronoun which and that.

The pronoun which or that is used to start a relative clause describing things.

Examples:

I bought a pony which/that eats like a horse. (= eats a lot)
I have a watch which/that nowadays tells different time. (= not accurate)

Relative pronoun whom

The relative pronoun whom is used for people. It is the object of the verb that follows it. Even though whom is the object of the relative clause, it comes at the beginning of the clause just like the other relative pronouns which are subjects of the clause.

Examples:

A friend whom I have known since childhood has grown much fatter than me.
His son whom we hired is a skilled ant eliminator.
The deceased is a close friend whom we will sadly miss.

Relative clause modifying whole sentence

So far, we have been talking about a relative clause describing a noun. We can also use a relative clause to describe the whole main clause. Such relative clause usually starts with the relative pronoun which. A comma is used before the relative pronoun.

Examples:

Look at the two old men fighting, which is very childish.
Dad refused to lend me his car, which is very disappointing.
The restaurant charges us $100 for the meal, which is outrageously expensive.
The menu has a list of spicy dishes, which is the reason I suggested this restaurant.