Relative Clauses and Their Functions

Understanding Relative Clauses

Relative clauses are subordinate clauses that modify a noun or pronoun, adding essential or extra information. Mastering their forms and functions is crucial for clear, precise English writing and speaking. This course breaks down the most common types of relative clauses, the roles of relative pronouns, and handy memory tricks to help you choose the right structure every time.

1. Relative Pronouns: Who, Which, That, Whom, and Where

Relative pronouns introduce a relative clause and stand in for a noun or pronoun that appears earlier in the sentence. Their selection depends on two factors: the antecedent (person, thing, or place) and the grammatical function (subject, object, or complement).

Subject vs. Object

When the relative pronoun functions as the subject of the clause, use who for people and which for things. The pronoun that can also serve as a subject, but it cannot be used as a subject when the antecedent is a person in formal English.

• Who – subject for people (e.g., "the man who called")
• Which – subject for things (e.g., "the book which fell")
• That – subject for people or things in informal style (e.g., "the car that broke")
• Whom – object of a verb or preposition (formal) (e.g., "the person whom I met")
• Where – adverbial complement of place (e.g., "the house where I grew up")

Mnemonic Tips

• "That = no head" – remember that that never carries a subject role; it cannot be the subject of its clause.
• "Who does the action?" – if the pronoun is the doer, choose who for people.
• "Whom meets a preposition" – when a preposition precedes the pronoun, whom is the safe, formal choice.
• "Where = Where‑Here‑Environment" – always signals a place‑related adverbial complement.

2. Determinative (Restrictive) vs. Non‑Determinative (Non‑Restrictive) Relative Clauses

Relative clauses fall into two broad categories based on how essential they are to the meaning of the sentence.

Determinative (Restrictive) Clauses

A determinative clause provides information that identifies the noun it modifies. Without it, the sentence would become ambiguous or lose a key detail.

• Usually no commas are used.
• Often introduced by who, which, that.
• Example: "The man who was speaking to you is my father." The clause tells us exactly which man is meant.

Non‑Determinative (Non‑Restrictive) Clauses

These clauses add extra, non‑essential information. The main idea of the sentence remains clear if the clause is removed.

• Set off by commas (or dashes).
• Often introduced by who, which, whose but never that in formal writing.
• Example: "The students, who learnt the lesson and did the exercises, passed easily." The clause is informative but not required to identify the students.

How to Test the Type

• Remove the clause. If the sentence still conveys the intended meaning, it is non‑determinative.
• If the meaning becomes vague or changes, the clause is determinative.

3. Zero Relative Pronouns

In many sentences, the relative pronoun can be omitted without harming grammaticality. This is called a zero relative pronoun. The omission typically occurs when the pronoun would serve as the direct object of the relative clause.

Typical Contexts

• After a noun, the verb of the relative clause follows immediately.

  Example: "The movie I saw yesterday was boring." (Underlying: "the movie that I saw…")

• When the clause is short and the meaning is clear.

When Not to Omit

• If the pronoun would be the subject of the clause (e.g., "the man who called") – omission would be ungrammatical.
• If the clause is non‑restrictive and set off by commas; the pronoun helps signal the extra information.

Memory Aid

"Zero = nothing to say, the verb follows the noun directly." Try inserting "that/who/which" mentally; if the sentence still sounds natural, the pronoun was already zero.

4. Functions of Relative Pronouns Beyond Subject/Object

Relative pronouns can also act as adverbial complements, indicating time, place, or reason.

Place: where

In "the hospital where I was born no longer exists," the pronoun where introduces a complement of place. It answers the question "where?" and functions as an adverbial phrase, not as a subject or object.

Time and Reason

Other relative adverbs include when (time) and why (reason). They similarly serve as adverbial complements.

• "That was the year when we met."
• "She gave a reason why she left."

Mnemonic

"WHERE = Where‑Here‑Environment" – always signals a location adverbial.

5. Choosing the Correct Pronoun for Prepositional Complements

When a relative pronoun follows a preposition, formal English prefers whom for people and which for things.

Example: "The people whom she spoke to were friendly." The preposition to governs the pronoun, so whom is the appropriate choice.

Key Points

• Place the preposition before the pronoun for formal style: to whom, for whom, with whom.
• In informal speech, many speakers use who or that after a preposition, but the exam‑type rule prefers whom.

Memory Trick

"Whom = W ho Meets preposition." Whenever a preposition precedes the pronoun, think of whom.

6. Summary of Common Errors and How to Avoid Them

• Using that as a subject for people – remember that that cannot serve as the subject of a relative clause.
• Confusing determinative and non‑determinative clauses – test by removing the clause; if the sentence stays clear, it is non‑determinative.
• Omitting the pronoun when it should be present – never drop the pronoun if it would be the subject of the relative clause.
• Choosing the wrong pronoun after a preposition – default to whom for people in formal contexts.
• Misidentifying adverbial complements – ask "where?", "when?", or "why?"; if the answer is a location, time, or reason, the relative word is an adverbial complement.

7. Practice Questions with Explanations

Use the following questions to test your understanding. Review the explanations to reinforce the concepts.

Question 1

Which relative pronoun cannot be used as the subject of a relative clause?

• which
• who
• that (correct)
• whom

Explanation: That never functions as a subject; the subject pronouns are who (people) and which (things).

Question 2

In the sentence "the man who was speaking to you is my father", what type of relative clause is used?

• appositive
• non‑determinative
• determinative (correct)
• generic

Explanation: The clause identifies which man is meant, so it is a restrictive (determinative) clause.

Question 3

Choose the correct relative pronoun: "The people ___ she praised were delighted."

• that
• whom
• who (correct)
• which

Explanation: The pronoun is the subject of "praised" and refers to people, so who is required.

Question 4

When a relative clause can be removed without changing the reference of the noun, it is:

• non‑determinative (correct)
• essential
• determinative
• restrictive

Question 5

Identify the function of the relative pronoun in "the hospital where I was born no longer exists".

• possessive complement
• direct object of the verb
• subject of the verb
• adverbial complement (correct)

Question 6

Which sentence contains a zero relative pronoun?

• The movie I saw yesterday was boring. (correct)
• The book that I read was fascinating.
• The person who called is waiting.
• The house which we bought needs repairs.

Question 7

In "the students, who learnt the lesson and did the exercises, passed easily", the relative clause is:

• non‑determinative (correct)
• appositive
• restrictive
• determinative

Question 8

Select the appropriate relative pronoun for the complement of a preposition: "the people ___ she spoke to were friendly".

• who
• whom (correct)
• which
• that

8. Final Tips for Mastery

• Always ask what role the pronoun plays: subject, object, or adverbial.
• Check whether the clause is essential; if it can be omitted, use commas and avoid that.
• When in doubt, replace the pronoun with the full noun phrase; if the sentence still works, you likely have a zero pronoun.
• Practice with authentic sentences and rewrite them, swapping pronouns and adding/removing commas to see the effect.

By internalising these patterns and mnemonic devices, you will choose the correct relative clause structure instinctively, improving both your written and spoken English.