Advanced Relative & Nominal Clauses (IELTS, TOEFL, YDS Practice) – C1 Grammar Test
This C1 grammar test focuses on structures used to:
refer to ideas, not just nouns
build compressed academic sentences
embed arguments inside clauses
control reference and abstraction
Choose the correct answer.
RESULTS
#1. The experiment failed to replicate the results, ___ raises serious concerns.
#2. What the study demonstrates ___ that environmental factors cannot be ignored.
#3. The researcher presented evidence ___ the theory required revision.
#4. The participants, many of ___ had no prior experience, struggled initially.
#5. The phenomenon ___ the article refers has yet to be fully explained.
#6. The proposal, ___ last year, has since been widely criticized.
#7. The committee rejected the claim, ___ they considered unsupported.
#8. There is growing evidence ___ early exposure affects cognitive development.
#9. She failed to address the central issue, ___ undermined the entire argument.
#10. The conclusion he reached was not ___ the data actually suggested.
#11. The policy is based on assumptions ___ validity remains uncertain.
#12. The factors ___ influence motivation are complex and interrelated.
#13. The most striking feature of the study is ___ it challenges existing models.
#14. The report contains several recommendations, none of ___ have been implemented.
#15. The theory attempts to explain ___ some species adapt more rapidly than others.
✅ Answer Key with VERY DETAILED EXPLANATIONS
🧠 C1 Relative & Nominal Clause Logic (IELTS · TOEFL · YDS)
🔑 Core C1 Principle
At C1 level, clauses are used to:
• refer to whole ideas, not just nouns
• turn statements into concepts
• compress information
• embed evaluation and argument
The exams test whether you can manage:
👉 reference, abstraction, and clause hierarchy
1. which
“Which” here refers to the entire previous clause, not just “results.”
This is a reference relative clause.
…failed to replicate the results, which raises serious concerns.
❌ that → cannot refer to a whole idea
❌ what → never follows a comma
Exam focus: IELTS cohesion & academic referencing.
2. is
“What the study demonstrates” is a nominal clause acting as a singular subject.
Therefore, the verb must be singular.
Exam focus: clause-as-subject agreement.
3. that
“Evidence that…” introduces a noun clause explaining the content of “evidence.”
❌ which → relative, not content
❌ what → cannot follow a noun
Exam focus: TOEFL/YDS noun-clause traps.
4. whom
“Many of whom” refers to people and functions as an object.
Structure: many of + whom
Exam focus: preposition + relative pronoun accuracy.
5. to which
“Refer to” requires the preposition to.
At C1, the preposition is often placed before the relative pronoun.
Exam focus: formal relative structures.
6. submitted
This is a reduced passive non-defining relative clause.
Full form:
which was submitted last year
Reduced C1 form:
submitted last year
Exam focus: academic compression.
7. which
“Which they considered unsupported” refers back to the whole claim.
It is not defining “claim,” but commenting on it.
Exam focus: reference vs defining clauses.
8. that
“Evidence that…” again introduces content, not description.
Exam focus: abstract noun + clause control.
9. which
Refers to the entire first clause:
“Her failure to address the issue” caused the problem.
Exam focus: cause–effect referencing.
10. what
“What the data actually suggested” is a nominal clause meaning ‘the thing that.’
Structure:
not what the data suggested
Exam focus: nominal relative clauses.
11. whose
“Whose” expresses abstract possession.
assumptions’ validity → whose validity
Exam focus: high-level relative precision.
12. that
Defining relative clause identifying “factors.”
“What” cannot modify a noun.
Exam focus: relative vs nominal distinction.
13. that
After “The most striking feature is…”, that-clauses introduce explanation.
Exam focus: academic definition structures.
14. which
“None of which” refers to the recommendations as a group.
“that” is never used after a comma.
Exam focus: non-defining relative mastery.
15. why
“Explain why” introduces a reason clause.
Exam focus: abstract question embedding.
🧠 C1 Clause Survival Summary
At C1 level, clauses allow you to:
• talk about ideas as objects
• evaluate arguments
• link causes and effects
• compress academic writing
• sound analytical, not narrative
This grammar dominates:
IELTS Writing Task 2
TOEFL integrated writing & reading
YDS advanced grammar sections
