A clause is a group of words with a subject and a finite verb (a verb that shows tense, such as left, is, or will call). An independent clause expresses a complete thought and can stand alone as a sentence: The train left early. A dependent clause, also called a subordinate clause, has a subject and verb too, but it begins with a word like because, when, that, or who, so it cannot stand alone: because the train left early.
Dependent clauses come in three types, named after the job they do: adverb (adverbial) clauses answer when, why, or under what condition; relative (adjective) clauses describe a noun; and noun clauses act as a subject or object. The 30 exercises below train you to spot each one, tell clauses from phrases, and fix the fragments that appear when a dependent clause is left on its own.
Clauses Quiz: 30 Questions
Warm-up · clause or not, independent or dependent
Core · adverb, relative, and noun clauses
Challenge · tricky clauses and clause vs phrase
Answer key and explanationsOpen after you finish the quiz.
- 1. because the printer jammedBecause the printer jammed has a subject (the printer) and a finite verb (jammed), so it is a clause. The other three are phrases: two prepositional phrases and an -ing phrase, none with a subject and finite verb.
- 2. Independent clauseThe train left early has a subject (the train) and a finite verb (left), and nothing makes it depend on another clause. It expresses a complete thought, so it is an independent clause and can stand as a sentence.
- 3. A dependent clauseIt has a subject (the store) and a finite verb (opens), so it is a clause, not a phrase. The subordinating conjunction when makes it dependent: it leaves the reader waiting for the main clause.
- 4. althoughAlthough is a subordinating conjunction, so although she called cannot stand alone. And is a coordinating conjunction, while then and also are adverbs; none of them make the clause dependent.
- 5. FragmentBecause makes the clause dependent, and there is no independent clause for it to attach to. The fix is to add one: Because we missed the bus, we walked.
- 6. my sister / boughtMy sister does the buying, so it is the subject, and bought is the finite verb. That is the relative pronoun standing in for the car, which is the object of bought.
- 7. TwoThere are two subject-verb pairs: I stayed (independent clause) and I was (inside the dependent clause because I was sick). Counting finite verbs is the quickest way to count clauses.
- 8. during the stormDuring is a preposition, and during the storm has no verb, so it is a prepositional phrase. Each of the others has a subject and a finite verb (she slept, it rains, he left).
- 9. A comma plus the coordinating conjunction soSo is one of the coordinating conjunctions (for, and, nor, but, or, yet, so). A comma plus a coordinating conjunction is a standard way to join two independent clauses; a comma alone would be a comma splice.
- 10. because, although, ifBecause, although, and if each introduce a dependent clause. And, but, and or are coordinating conjunctions; however, therefore, and moreover are conjunctive adverbs; in, on, and at are prepositions.
- 11. Relative (adjective) clauseThe clause describes the noun book and tells us which book, so it is a relative (adjective) clause. The relative pronoun that refers back to book.
- 12. Noun clauseThe clause is the object of know: you could replace it with a noun or pronoun (I know it). There is no noun before it for it to describe, so it is a noun clause, not a relative clause.
- 13. Adverb clauseThe clause answers when we left, so it modifies the verb and works like an adverb. Adverb clauses usually begin with subordinating conjunctions such as before, because, if, or although.
- 14. Noun clause acting as the subjectWhat she said is the subject of surprised; you could swap in a noun (Her comment surprised everyone). A clause that fills a noun slot, such as subject or object, is a noun clause.
- 15. Relative clauseThe clause describes the noun town (where means in which), so it is a relative clause. Where, when, and why can introduce relative clauses when they follow a noun of place, time, or reason.
- 16. Adverb clause of conditionIf introduces a condition for the main action (call me), so this is an adverb clause of condition. It modifies the verb call rather than describing a noun or filling a noun slot.
- 17. Noun clauseThe clause is the object of wonder (I wonder something). Clauses beginning with whether, if (meaning whether), that, or a question word often act as noun clauses after verbs like know, ask, and wonder.
- 18. I'll text you when I land.When I land has a subject and finite verb introduced by when, so it is a dependent clause. Smiled and waved share one subject in one clause, and in the blue coat and after lunch are phrases.
- 19. The results were good.The results were good is an independent clause. Which was a surprise and although the results were good are dependent clauses left on their own, and since the day we met is a phrase with a clause inside it, so all three are fragments.
- 20. I bought a new laptop because my old one broke.Attach the dependent clause to the main clause. When a because clause follows the main clause, it normally needs no comma. A semicolon cannot be used here because it joins independent clauses, not a main clause and a dependent one.
- 21. Relative clauseThe clause follows and describes the noun reason, so it is a relative clause; why here means for which. Compare I don't know why he quit, where the clause is the object of know and is a noun clause.
- 22. Noun clauseThe clause is the subject of is (The start time is up to you), so it is a noun clause. Compare When the film starts, turn off your phone, where the same words modify the verb and form an adverb clause.
- 23. Noun clauseThere is no noun before the clause for it to describe; it is the object of remember (I remember that moment). In I remember the day when we met, the clause describes day and would be a relative clause.
- 24. [Having finished the report], she went home.Having finished the report has no subject and no finite verb (having finished is a participle), so it is a participial phrase. Each of the others contains a subject and a finite verb: she finished, she had finished, the report was.
- 25. FourCount the finite verbs: the man said (independent), who called (relative clause), that he would come back (noun clause), and when the office opened (adverb clause). Four finite verbs, four clauses.
- 26. When the alarm rang, I jumped out of bed.When a dependent clause comes before the main clause, the standard rule is a comma after it. Some writers drop the comma after a very short opener, but the comma is always correct. A semicolon cannot separate a dependent clause from its main clause.
- 27. Because it was snowing, we cancelled the trip.Adding because subordinates the first clause. The so and semicolon versions are correct but keep both clauses independent. The first option is a comma splice: two independent clauses joined only by a comma.
- 28. The guests who arrived late.Who arrived late is a relative clause describing guests, but the guests never gets a main verb of its own, so there is no independent clause. Stop is a complete imperative sentence with an understood subject (you).
- 29. the subject of the sentence (a noun clause)Whoever finishes first is the subject of wins (The winner wins a prize), so it is a noun clause. A comma would wrongly split the subject from its verb.
- 30. I was tired, I went to bed.I was tired and I went to bed are both independent clauses, and a comma alone cannot join them. Fix it with a coordinating conjunction (so), a subordinating conjunction (because), a semicolon, or a full stop.
What Is a Clause? Subject + Finite Verb
Every clause has two parts: a subject (who or what the clause is about) and a finite verb (a verb marked for tense or person, such as runs, ran, is, has eaten, or will go). Infinitives (to run) and -ing or -ed participles on their own (running, finished) are not finite, so they do not make a clause by themselves.
That is the whole difference between a clause and a phrase. A phrase is a group of words without a subject-and-finite-verb pair: in the morning, the tall man, having finished lunch. A clause always has one: the man left, because it rained, who lives here.
- Clause: she sings (subject she + finite verb sings).
- Clause: although the price rose (subject the price + finite verb rose).
- Phrase: after the concert (preposition + noun, no verb).
- Phrase: to win the race (infinitive, not finite).
- Phrase: walking to school (participle, no subject).
To count clauses, count finite verbs. Each finite verb normally signals one clause.
Independent vs Dependent (Subordinate) Clauses
An independent clause is complete on its own: I made coffee. A dependent clause, also called a subordinate clause, has a subject and verb but begins with a subordinating word, so it needs an independent clause to finish the thought: when I woke up. Together they make one sentence: When I woke up, I made coffee.
The subordinating word is what makes the difference. Put because, although, if, when, since, or until in front of an independent clause and it becomes dependent. Relative words (who, which, that, whose) and noun-clause words (that, whether, what, how) do the same job. The full list is in our guide to subordinating conjunctions.
- Independent: The meeting ended.
- Dependent: after the meeting ended
- Sentence: After the meeting ended, we went for lunch.
- Two independent clauses: The meeting ended, and we went for lunch.
Read the clause aloud by itself. If it leaves you waiting (because the meeting ended… what?), it is dependent.
The Three Types of Dependent Clause
Dependent clauses are classified by the job they do in the sentence, not by the word they start with. The same word can open different types: when opens an adverb clause in Call me when you land, a relative clause in the day when we met, and a noun clause in I don't know when he left.
- Adverb (adverbial) clause: modifies the verb or the whole main clause and answers when, why, where, how, or under what condition. Example: We stayed inside because it was raining.
- Relative (adjective) clause: describes a noun and starts with who, whom, whose, which, that, where, when, or why. Example: The woman who called is my aunt.
- Noun clause: does the job of a noun, as subject, object, or complement. Example: I know that she's right. / What he said was true.
- Test for a noun clause: replace it with it or something. If the sentence still works (I know it), it is a noun clause.
- Test for a relative clause: it comes right after a noun and tells you which one or more about it.
Relative clauses have their own rules for commas and for choosing who, which, or that. See our relative clauses guide for the details.
Fragments: When a Dependent Clause Stands Alone
A sentence fragment is a group of words punctuated as a sentence that has no independent clause. The most common type is a dependent clause cut off by a full stop: I left early. Because I was tired. The fix is to join it to the nearby main clause: I left early because I was tired.
Fragments are not always errors. Writers use them deliberately in ads, dialogue, and informal writing (Not bad. Worth a try.). In formal and academic writing, though, each sentence should contain at least one independent clause.
- Fragment: Which was a mistake. Fix: I sold the car, which was a mistake.
- Fragment: Although the plan looked good. Fix: Although the plan looked good, it failed.
- Fragment: The students who passed the test. Fix: The students who passed the test got certificates.
- Comma splice (a different error): It rained, we stayed in. Fix: It rained, so we stayed in.
How Clauses Build Sentence Types
The number and type of clauses decide the sentence type. A simple sentence has one independent clause. A compound sentence joins two or more independent clauses. A complex sentence has one independent clause plus at least one dependent clause, and a compound-complex sentence has at least two independent clauses and at least one dependent clause. Our complex sentences guide covers how to build and punctuate each type.
Keep practicing
Frequently Asked Questions
What is the difference between an independent and a dependent clause?
Both have a subject and a finite verb. An independent clause expresses a complete thought and can stand alone as a sentence (She left). A dependent clause starts with a subordinating word such as because, when, who, or that, so it cannot stand alone (because she left) and must be attached to an independent clause.
Is a subordinate clause the same as a dependent clause?
Yes. Subordinate clause and dependent clause are two names for the same thing: a clause that cannot stand alone as a sentence. Main clause is likewise another name for an independent clause.
What is the difference between a clause and a phrase?
A clause contains a subject and a finite verb (because the bus was late). A phrase does not (because of the late bus, after lunch, to be honest). Both can add information to a sentence, but only a clause can be a sentence or become one.
Check Your Sentences for Fragments and Comma Splices
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