C1 Mixed Grammar – 30 Advanced Questions for IELTS, TOEFL & YDS | Test 1 | EnglishTestCenter
Take C1 Mixed Grammar Test 1 with 30 advanced multiple-choice questions covering tense, modals, clauses, passives, conditionals, and more. Perfect for IELTS, TOEFL, and YDS preparation with detailed explanations.
This comprehensive C1-level mixed grammar test is designed for candidates preparing for high-stakes proficiency exams such as IELTS, TOEFL, and YDS. At this level, learners must demonstrate accurate control of advanced grammatical structures, including:
Complex tenses and aspect combinations
Modal verbs for deduction and probability
Conditionals (mixed and inverted forms)
Passive and causative structures
Relative and nominal clauses
Participle clauses
Preposition + relative pronoun constructions
Advanced connectors and discourse markers
The questions below assess grammatical precision, structural awareness, and academic-level control expected at C1.
Instructions: Choose the best answer for each question.
RESULTS
#1. By the time the conference begins, the committee ______ the final agenda.
#2. She speaks as though she ______ the entire situation herself.
#3. The proposal, ______ was submitted last week, has not yet been reviewed.
#4. He denied ______ any confidential information.
#5. Hardly ______ the announcement made when the media reacted strongly.
#6. The results appear ______ inconsistent with previous findings.
#7. If she ______ more thoroughly, she might have avoided the error.
#8. The company is said ______ a major breakthrough.
#9. Not only ______ increase efficiency, but it also reduced costs.
#10. The manager insisted that the report ______ by Friday.
#11. She would rather you ______ the issue immediately.
#12. The data, some of ______ were incomplete, required further analysis.
#13. He must ______ the instructions incorrectly.
#14. The project was delayed due to problems ______ during implementation.
#15. It is essential that every participant ______ the guidelines carefully.
#16. The lecture was so complex that few students could follow ______.
#17. She had her assistant ______ the documents before submission.
#18. No sooner ______ the results published than criticism emerged.
#19. The theory is widely regarded ______ outdated.
#20. The researcher objected to ______ excluded from the discussion.
#21. Only after the investigation ______ the full extent of the issue revealed.
#22. The students were unsure ______ the deadline had been extended.
#23. Having ______ the evidence, the jury reached a verdict.
#24. He is believed ______ involved in the negotiations.
#25. The policy aims to prevent errors rather than ______ them afterward.
#26. Were the proposal ______ earlier, it might have been approved.
#27. She asked me where I ______ the information.
#28. The committee decided to postpone the meeting, ______ surprised many members.
#29. He would have succeeded if he ______ more persistent.
#30. The evidence is not sufficient to conclude ______ the hypothesis is valid.
Detailed Explanations (All Answers Explained Together)
Below you will find extremely detailed, in-depth grammatical analyses of all correct answers. Each explanation focuses exclusively on the correct answer word and examines the underlying grammatical rule, structural reasoning, register considerations, and exam relevance (IELTS, TOEFL, YDS).
1. will have approved
The structure requires the future perfect tense, which is used to describe an action that will be completed before a specific point in the future. The time clause “By the time the conference begins” establishes a clear future reference point. When a future action is completed before another future action, English requires future perfect rather than simple future. This tense demonstrates advanced temporal control and sequencing ability, which is a key C1 skill. It reflects mastery of aspect (completion before a future reference point), not just tense.
2. had experienced
The expression “as though” introduces an unreal comparison. When the comparison refers to a past situation that is hypothetical or contrary to fact, the past perfect is required. This tense distances the speaker from reality and signals that the experience did not actually occur. At C1 level, candidates must distinguish between real past comparison (past simple) and unreal or imagined past comparison (past perfect). This reflects advanced modal remoteness and counterfactual control.
3. which
This is a non-defining relative clause, identified by the commas. Non-defining clauses provide additional, non-essential information and must use a relative pronoun appropriate for things. At advanced levels, learners must distinguish between defining and non-defining clauses, understand punctuation dependency, and avoid incorrect use of alternative pronouns. The comma signals that the clause is supplementary, not restrictive, which grammatically requires this relative form.
4. leaking
The verb “deny” belongs to a group of verbs that are obligatorily followed by a gerund (-ing form). This is not optional and cannot be replaced by an infinitive. Mastery of verb pattern complementation (gerund vs. infinitive) is a critical C1 grammar feature frequently tested in TOEFL and YDS. The gerund here functions as a direct object noun phrase.
5. had been
The adverbial “hardly” placed at the beginning triggers subject-auxiliary inversion, a formal structure typical in academic English. Additionally, the timeline requires past perfect because one action occurred immediately before another past action. The passive form is required because the subject receives the action. This combines three advanced grammar features: inversion, perfect aspect, and passive voice.
6. to be
The verb “appear” functions as a linking verb and must be followed by a to-infinitive structure when describing states or conditions. This pattern is part of raising verb constructions common in academic English. C1 learners must recognize that certain reporting or perception verbs require infinitival complements rather than gerunds or base forms.
7. had prepared
This sentence expresses a third conditional, describing a hypothetical past situation with a past result. The if-clause must use past perfect to signal that the condition did not occur. Mastery of conditional types, especially perfect conditionals, demonstrates high-level control of tense sequencing and hypothetical reasoning.
8. to have achieved
This is a passive reporting structure referring to a past action. When the reporting verb is in present form but the reported action occurred earlier, English requires the perfect infinitive. This structure shows advanced understanding of time layering within reporting constructions.
9. did the strategy
When “not only” appears at the beginning of a clause, inversion is mandatory. The auxiliary precedes the subject. This structure is typical in formal and academic emphasis. Recognizing inversion triggers is a hallmark of C1 grammatical competence.
10. be completed
After verbs expressing demand, insistence, recommendation, or necessity, English uses the mandative subjunctive, which takes the base form of the verb regardless of subject. This form is particularly common in formal and academic contexts and highly tested in advanced exams.
11. addressed
The structure “would rather” followed by a different subject requires past simple to express present or future preference. This reflects modal distancing, not past time. Understanding this subtle use of tense for politeness or hypothetical meaning is a strong indicator of C1 proficiency.
12. which
When a relative pronoun follows a preposition (“some of”), the structure requires a formal relative pronoun appropriate for things. This is an example of preposition + relative pronoun construction, a complex clause structure typical of academic writing.
13. have interpreted
Modal verbs expressing deduction about the past require modal + have + past participle. This structure indicates logical inference about a completed action. Mastery of epistemic modality in past contexts is central to C1 stance control.
14. arising
This is a reduced relative clause, also called a participle clause. It condenses “which arose” into a more formal and concise structure. Such reductions are common in academic texts and signal syntactic flexibility.
15. read
After expressions like “It is essential that,” English uses the subjunctive base form. The verb does not change for third person singular. This construction shows advanced control of formal necessity expressions.
16. it
Pronoun reference must agree in number with its antecedent. “Lecture” is singular and uncountable in this context, so singular pronoun agreement is required. Precision in reference tracking is crucial in academic writing.
17. check
In active causative constructions (“have someone do something”), the verb following the object takes the base form. This structure expresses delegation of action and is frequently tested at upper-intermediate and advanced levels.
18. had been
“No sooner” triggers inversion and requires past perfect for the earlier action in a sequence. This structure emphasizes immediacy between two past events and is characteristic of formal narrative style.
19. as
“Regarded” requires the preposition as to express classification or identification. Collocational competence is essential at C1, as many verbs require fixed prepositions.
20. being
When a verb is followed by a preposition (“objected to”), the complement must be a gerund. Prepositions cannot be followed by infinitives. This rule is fundamental but frequently tested in complex contexts.
21. was
“Only after” at the beginning triggers inversion in the main clause. Since the event refers to a completed past action in passive form, simple past passive is required. This combines inversion with passive voice accuracy.
22. whether
Indirect yes/no questions in formal contexts require whether, especially when functioning as a clause complement. This reflects academic register preference.
23. considered
Perfect participle clauses use having + past participle or simply past participle in reduced form to indicate prior completion. This demonstrates advanced clause compression techniques.
24. to be
Passive reporting structures require infinitival complements. The infinitive indicates reported belief without asserting direct knowledge, a key feature of academic hedging.
25. correcting
After “rather than,” parallel grammatical form is required. Since the first element implies a gerund structure, the second must also be a gerund. Parallelism is essential in formal writing.
26. submitted
This is an inverted conditional omitting “if.” In passive constructions, the past participle appears directly after the subject. Such inversion is stylistically formal and common in academic prose.
27. had found
In reported speech, when the reporting verb is in the past, earlier past actions shift to past perfect. This backshifting demonstrates mastery of sequence of tenses.
28. which
When referring to an entire preceding clause rather than a single noun, a non-defining relative clause requires which. This is a higher-level discourse referencing device.
29. had been
Third conditional structures require past perfect in the condition clause. This signals that the condition was unreal and refers to a finished past situation.
30. that
The verb “conclude” requires a that-clause when introducing a declarative noun clause. This is a formal reporting structure typical of academic and research writing.
