Complex Sentences Grammar Quiz

Test your ability to build complex sentences in English. This quiz covers subordinate clauses, relative clauses, participle clauses, and adverbial clauses across B1 to C1 level — skills essential for high-scoring IELTS and Cambridge writing.

20 questions B1–C1 level Grammar Free · No sign-up
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What This Quiz Tests

Complex sentences contain at least one independent clause and one subordinate clause. Using them accurately and confidently is a sign of advanced grammar. This quiz tests your ability to identify, form, and combine complex sentence structures.

  • Relative clauses: defining and non-defining, using who, which, that, whose, where, when.
  • Adverbial clauses: time (when, after, as soon as), reason (because, since), concession (although, even though), condition (if, unless).
  • Noun clauses: used as subjects, objects, and complements (I know that he is right).
  • Participle clauses: present and past participle structures to reduce complexity (Having finished the report, she left).
  • Sentence combining: joining two or more clauses appropriately using subordinating conjunctions.

Choose Your Format

Practise the same topic in four different exercise formats:

Sample Questions

1. Choose the correct relative pronoun: “The woman ___ car was stolen reported it to the police.”

Answer: whose

2. Which type of clause is this? “Having submitted the form, you will receive a confirmation email.”

Answer: Participle clause (past/perfect participle)

3. Combine using a concession clause: “It was raining. We went for a walk.” → ___ it was raining, we went for a walk.

Answer: Although / Even though

CEFR Level Breakdown

LevelWhat to expect
B1Basic relative clauses (who, which, that), common adverbial clauses
B2Non-defining relative clauses, participle clauses, adverbial clause variety
C1Complex noun clauses, reduced clauses, formal academic sentence structures

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Frequently Asked Questions

A complex sentence contains at least one independent clause (which can stand alone) and at least one subordinate (dependent) clause (which cannot stand alone). The clauses are joined by a subordinating conjunction such as because, although, when, if, or who. Example: 'She left early because she had a meeting.'

A compound sentence joins two independent clauses using coordinating conjunctions (and, but, or, so): 'I was tired, but I finished the report.' A complex sentence uses a subordinating conjunction: 'Although I was tired, I finished the report.' A compound-complex sentence combines both: two independent clauses and at least one subordinate clause.

The main types are: relative clauses (The man who called is my uncle), adverbial clauses of time (I'll call you when I arrive), reason (She left because she was ill), condition (If it rains, we'll cancel), concession (Although he studied hard, he failed), and noun clauses used as subjects or objects (I know that she is right).

A defining (restrictive) relative clause identifies which person or thing is being referred to: 'The book that I recommended is out of print.' A non-defining (non-restrictive) relative clause adds extra information — it is separated by commas: 'My brother, who lives in Paris, is a chef.' Note that 'that' is NOT used in non-defining clauses.

A participle clause uses the present participle (-ing form) or past participle (-ed form) instead of a full subordinate clause. 'After she finished the report, she sent it' becomes 'Having finished the report, she sent it.' The subject of the participle clause must be the same as the main clause subject, or you create a dangling participle error.

A noun clause is a subordinate clause that functions as a noun — it can be the subject, object, or complement. Noun clauses are introduced by 'that', 'whether', 'if', or wh-words. Examples: 'What she said surprised everyone.' (subject), 'I believe that he is right.' (object), 'The problem is that we lack data.' (complement).

In IELTS Writing, the Grammatical Range and Accuracy band descriptor rewards a range of sentence structures including complex sentences with relative clauses, conditional clauses, and participle clauses. Using only simple sentences limits you to Band 5 or 6. Accurately using complex structures is key to achieving Band 7 and above.

'Although' and 'even though' both introduce concessive clauses showing contrast, and they are largely interchangeable. 'Even though' is slightly more emphatic, stressing a stronger or more surprising contrast. 'Although' is more neutral. Both are more formal than 'but'.

To avoid run-on sentences: (1) use a full stop to separate independent clauses; (2) use a semicolon; (3) use a coordinating conjunction (and, but, so); (4) use a subordinating conjunction to make one clause dependent. Always check that subordinate clauses are attached to a main clause and not floating alone.

Yes. Complex sentence structures are tested directly in the Cambridge B2 First Key Word Transformation task, where you must rewrite sentences using a given word — often requiring relative clauses, participle clauses, or subordinating conjunctions. The Writing paper also assesses grammatical range and accuracy.