5.4 Relative Clauses and Noun Clauses

Key Takeaways

  • Relative clauses modify nouns: restrictive (essential, often no commas, that/who/which) vs nonrestrictive (extra info, commas, who/which—not that in careful formal style).
  • Choose who (people subject), whom (people object, formal), which (things), that (people/things in restrictive clauses), whose (possession), where/when/why (place/time/reason).
  • Reduced relatives drop who/which/that + be (*the students selected*, *the policy adopted last year*) when meaning stays clear.
  • Noun clauses act as subjects/objects with that, whether/if, or wh- words; after verbs like know, ask, wonder, keep statement word order (*I wonder where she is*, not where is she).
  • Embedded questions never invert like direct questions; *Do you know what time it is?* not *what time is it* inside the clause without reinversion care—on iTEP, prefer subject–verb statement order after the wh- word.
Last updated: August 2026

5.4 Relative Clauses and Noun Clauses

Quick Answer: Relative clauses describe nouns (the student who applied); noun clauses act as nouns (I know that she applied / Whether she applied is unclear). iTEP tests marker choice (who/which/that/whose/where), restrictive vs nonrestrictive rules, reduced relatives, and embedded-question word order.

Relative clauses: job and position

A relative clause modifies a noun (the antecedent). It usually begins with a relative pronoun or adverb:

MarkerTypical antecedentRole
whopeoplesubject (and informal object)
whompeopleobject (formal)
whichthings / animals (non-person)subject or object
thatpeople or thingsrestrictive clauses
whosepeople or thingspossession
whereplacethe campus where…
whentimethe year when…
whyreasonthe reason why… (sometimes reduced)

Examples

  • Subject: Applicants who submit late files are waitlisted.
  • Object: The course that she recommended fills quickly. (object that can often be omitted: the course she recommended)
  • Possession: Students whose scores improve may retest sooner.
  • Place: The lab where the samples are stored needs renovation.

Restrictive vs nonrestrictive

TypeFunctionCommasthat
Restrictive (defining)identifies which oneusually no commasthat or who/which OK
Nonrestrictive (non-defining)adds extra info about a known nouncommasprefer who/which; avoid that in careful formal style
  • Restrictive: The students who scored above 4.0 received scholarships. (only those students)
  • Nonrestrictive: My advisor, who scored above 4.0 on iTEP years ago, recommended daily practice. (extra fact about a unique advisor)

iTEP trap: Using that after a comma for nonrestrictive people/things: Paris, that is beautiful,Paris, which is beautiful,

iTEP trap: which for people in careful academic English: prefer who for human antecedents when options contrast.

Omitting the relative pronoun

You may omit that/which/who(m) only when it is the object of the relative clause:

  • The book that I borrowedThe book I borrowed (OK)
  • The book that explains the method → cannot drop that (subject)

Error-ID items may mark a necessary subject relative as “missing,” or mark an incorrect object form (who vs whom) in formal stems.

Reduced relative clauses

Academic English often reduces who/which/that + be + adjective/participle:

FullReduced
students who are enrolled in Corestudents enrolled in Core
policies that were adopted in 2025policies adopted in 2025
researchers who work on phonologyresearchers working on phonology

Active meaning: present participle (working). Passive meaning: past participle (adopted). Fill-in options may offer both; match voice and time.

Do not reduce when meaning collapses or when a full finite verb is required by the options set.

Noun clauses: subjects, objects, complements

A noun clause fills a noun slot:

  1. Object: Researchers claim that the sample is biased.
  2. Subject: That the sample is biased is controversial. / Whether funding continues remains unclear.
  3. Complement: The question is whether scores will rise.
  4. After adjectives: I am confident that she will pass.

Common openers

  • that (statements; that often optional after many verbs: I think (that)…)
  • whether / if (yes/no content; whether preferred before or not and in subject position)
  • wh- words: what, who, whom, which, when, where, why, how, how much/many

Subject-position caution: That she passed surprised everyone is formal but correct. Starting with That… may feel heavy; on the exam, if the option is a full that-clause as subject, check verb agreement with the clause as a singular unit: That she passed was surprising.

Embedded questions (word order)

Direct question: Where is the testing center?
Embedded (noun clause): Do you know where the testing center is?

Wrong (inverted inside)Right (statement order)
I wonder where is she.I wonder where she is.
Tell me what did they decide.Tell me what they decided.
It is unclear why did scores drop.It is unclear why scores dropped.

This is one of the highest-yield advanced grammar traps on proficiency tests. If you see do/does/did or inverted is/are after a wh- word inside a larger sentence, suspect wrong embedded order.

Whether vs if: Both introduce yes/no noun clauses after many verbs (ask whether/if). Prefer whether before or not, after prepositions, and in subject position: Whether or not she retests is her choice.

Relative vs noun clause confusion

  • Relative: modifies a noun already present. The policy that failed was revised.
  • Noun: replaces a noun slot. I know that the policy failed.

If there is no antecedent noun for that/who to attach to, you are looking at a noun clause (or a missing head noun error).

Parallel academic patterns for drills

  • The metric by which success is measured… (preposition + relative)
  • The scholar to whom the award was given… (formal whom)
  • It is essential that each candidate submit a transcript (subjunctive preview; finite noun clause after essential that)
  • What matters most is consistent practice (what-clause as subject; singular verb often)

Strategy for iTEP Grammar items

  1. Find the gap’s job: noun modifier (relative) vs noun replacement (noun clause) vs full sentence connector.
  2. Check antecedent: person → who/whom/whose; thing → which/that; place/time → where/when.
  3. Restrictive vs extra info: commas and that restrictions.
  4. Embedded question: after know, ask, wonder, explain, unclear, force subject + verb order.
  5. Reduced relative: match participle voice to active/passive meaning.

Relative and noun clauses let writers pack definitions, evidence, and uncertainty into single academic sentences—exactly the register iTEP Grammar samples. When options differ only by who/which/that or by is she / she is, apply these rules mechanically and save deliberation time for meaning-heavy reading and listening items later in the exam day.

Test Your Knowledge

Which option correctly completes: “The applicants ____ portfolios arrived after the deadline were not interviewed”?

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Test Your Knowledge

Which sentence uses correct embedded-question word order?

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D
Test Your Knowledge

Identify the error in formal academic style: “Lake Victoria, that supports millions of people, is under environmental stress.”

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D
Test Your Knowledge

Which reduced form correctly matches “policies that were adopted last year”?

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D