relative pronoun

Relative pronouns are that, who, whom, whose, which, where, when, and why. They are used to join clauses to make a complex sentence. Relative pronouns are used at the beginning of the subordinate clause which gives some specific information about the main clause.

This is the house that Jack built.

I don't know the day when Jane marries him.

The professor, whom I respect, was tenured.

In English, the choice of the relative pronoun depends on the type of clause it is used in. There are two types of clauses distinguished: defining (restrictive) relative clauses and non-defining (non-restrictive) relative clauses. In both types of clauses the relative pronoun can function as a subject, an object, or a possessive.

Relative pronouns in defining clauses

Defining relative clauses (also known as restrictive relative clauses) provide some essential information that explains the main clause. The information is crucial for understanding the sentence correctly and cannot be omitted. Defining clauses are opened by a relative pronoun and ARE NOT separated by a comma from the main clause.

The table below sums up the use of relative pronouns in defining clauses:

Function in the sentence	Reference to
	People	Things / concepts	Place	Time	Reason
Subject	who, that	which, that
Object	(that, who, whom)*	(which, that)*	where	when	why
Possessive	whose	whose, of which

Examples

Relative pronoun used as a subject:

This is the house that had a great Christmas decoration.

It took me a while to get used to people who eat pop-corn during the movie.

Relative pronoun used as an object:

1) As can be seen from the table, referring to a person or thing, the relative pronoun may be omitted in the object position:

This is the man (who / that) I wanted to speak to and whose name I'd forgotten.

The library didn't have the book (which / that) I wanted.

I didn't like the book (which / that) John gave me.

This is the house where I lived when I first came to the US.

2) whom:
In American English, whom is not used very often. Whom is more formal than who and is very often omitted in speech:

Grammatically Correct: The woman to whom you have just spoken is my teacher.

Common in Speech: The woman (who) you have just spoken to is my teacher.

However, whom may not be omitted if preceded by a preposition:

I have found you the tutor for whom you were looking.

Relative pronoun used as a possessive:

Whose is the only possessive relative pronoun is in English. It can be used with both people and things:

The family whose house burnt in the fire was immediately given a suite in a hotel.

The book whose author is now being shown in the news has become a bestseller.

General remarks: That, Who, Which compared

The relative pronoun that can only be used in defining clauses. It can also be substituted for who (referring to persons) or which (referring to things). That is often used in speech; who and which are more common in written English.

William Kellogg was the man that lived in the late 19th century and had some weird ideas about raising children. - spoken, less formal

William Kellogg was the man who lived in the late 19th century and had some weird ideas about raising children. - written, more formal

Although your computer may suggest to correct it, referring to things, which may be used in the defining clause to put additional emphasis on the explanation. Again, the sentence with which is more formal than the one with that: Note that since it is the defining clause, there is NO comma used preceding which:

The café that sells the best coffee in town has recently been closed. - less formal

The café which sells the best coffee in town has recently been closed. - more formal

Some special uses of relative pronouns in defining clauses

that / who
Referring to people, both that and who can be used. That may be used to refer to someone in general:

He is the kind of person that/who will never let you down.

I am looking for someone that/who could give me a ride to Chicago.

However, when a particular person is being spoken about, who is preferred:

The old lady who lives next door is a teacher.

The girl who wore a red dress attracted everybody's attention at the party.

that / which
There several cases when that is more appropriate than and is preferred to which:

After the pronouns all, any(thing), every(thing), few, little, many, much, no(thing), none, some(thing):

The police usually ask for every detail that helps identify the missing person. - that used as the subject

Marrying a congressman is all (that) she wants. - that used as the object

After verbs that answer the question WHAT? For example, say, suggest, state, declare, hope, think, write, etc. In this case, the whole relative clause functions as the object of the main clause:

Some people say (that) success is one percent of talent and ninety-nine percent of hard work.

The chairman stated at the meeting (that) his company is part of a big-time entertainment industry.

After the noun modified by an adjective in the superlative degree:

This is the funniest story (that) I have ever read! - that used as the object

After ordinal numbers, e.g., first, second, etc.:

The first draft (that) we submitted was really horrible. - that used as the object

If the verb in the main clause is a form of BE:

This is a claim that has absolutely no reason in it. - that used as the subject