Overview
A clause is a group of words that contains a subject and a verb. An independent clause expresses a complete thought and can stand alone as a sentence. A dependent (subordinate) clause cannot stand alone — it depends on a main clause to make sense. Understanding clauses is essential for building complex sentences correctly.
Types of Clauses
- IndependentCan stand alone as a sentence: She studies every day.
- DependentCannot stand alone — needs a main clause: Because she studies … (incomplete)
- RelativeDescribes a noun using who, which, that, whose, where: the book that I read
- NounFunctions as a noun — subject or object: What he said surprised everyone.
- AdverbialGives time, reason, or condition: Although it was late, she kept working.
Key Rules
- A sentence must have at least one independent clause.
- Dependent clauses are introduced by subordinating conjunctions: because, although, when, if, since, unless.
- Defining relative clauses — no commas: The man who called is my uncle.
- Non-defining relative clauses — use commas: My sister, who lives in Rome, is a chef.
- Use that only in defining clauses, never in non-defining ones.
Common Mistakes
- ❌ Because she was tired. (fragment — no main clause) → ✅ She left early because she was tired.
- ❌ The man which called → ✅ The man who called (use who for people)
- ❌ My sister, that lives in Rome → ✅ My sister, who lives in Rome (no that in non-defining clauses)
- ❌ The place where I was born it is beautiful → ✅ remove the extra pronoun it
When to use
Adding detail
The student who won the prize is very talented.
Giving reasons
She left early because she felt unwell.
Showing contrast
Although it rained, we enjoyed the trip.
Noun clauses
I know what she means.