Relative Clauses

A relative clause is a phrase that modifies a noun or pronoun. It is also a dependent or subordinate clause, meaning that it cannot stand on its own as a sentence. This handout explains the rules for using relative clauses and provides examples of correct use of relative clauses.

Positioning the Relative Clause

Put the relative clause directly behind the noun it modifies.

Original: The theory will be implemented that is most supportive of my work for the final project.

Revised: The theory that is most supportive of my work will be implemented for the final project.

Heading the Relative Clause with a Relative Pronoun (which)

Make sure there is a relative pronoun (which) at the head of the relative clause (preferably preceded by a preposition).

Original: The point water boils at is 212 degrees Fahrenheit.

Revised: The point at which water boils is 212 degrees Fahrenheit.

Avoiding a Duplication Pronoun

Be careful that you don't have a second pronoun duplicating the role of the relative pronoun.

Original: The theory that it is most supportive of my work will be implemented for the final project.

Revised: The theory that is most supportive of my work will be implemented for the final project.

Substituting "which" for "that"

You may substitute "which" for "that" if it is not preceded by a preposition.

Example: The ice cream (which, that) tastes the best is creamy and smooth.

Omitting the Relative Pronoun and Auxiliary Verb

If the relative clause begins with a relative pronoun and some form of the auxiliary verb "to be" and is followed by a verb phrase, you may omit the relative pronoun and auxiliary.

Example: The theory that is most supportive of my research will be implemented for the final project.

Can become: The theory most supportive of my research will be implemented for the final project.

In other words, you can omit any combination of relative pronoun and form of the verb "to be:" which is, which are, that is, that are, who is, that was, etc., if they are not immediately followed by a noun phrase or adjective phrase.

Using the -ing form

If the relative clause begins with a relative pronoun and a main verb (i.e., a nonauxiliary verb), you may omit the relative pronoun and change the verb to its -ing form.

Example: Students who take classes in the summer find the classroom environment to be more laid back and more amenable to students who want to focus on their extracurricular interests.

Can become: Students taking classes in the summer find the classroom environment to be more laid back and more amenable to students wanting to focus on their extracurricular interests.

However, this rule cannot be applied if the verb following the relative pronoun is an auxiliary verb, i.e., any form of the verb "to be," any modal verb (can, may, will, would, etc.), or any form of the verb "to have" when it is used as an auxiliary. Consider the following example.

Example: A hologram is a photographic image that is produced without using any lens.

Cannot be changed to: A hologram is a photographic image being produced without using any lens.

Sometimes the verb "to have" is used as the main verb, not an auxiliary, in which case the rule may be applied:

Example: A good paper is one (that has, having) a strong thesis statement and logical organization.

Omitting the Relative Pronoun

If the relative clause begins with a relative pronoun (which, that) and another pronoun (he, she, it, they, we, I), you may omit the relative pronoun.

Example: The free market system that we are all familiar with is increasingly under scrutiny.

Can become: The free market system we are all familiar with is increasingly under scrutiny.

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