An adverbial clause is a dependent clause (subject + verb) that functions like an adverb. It tells us when, where, why, how, with what result, or under what condition an action happens. It begins with a subordinating conjunction (e.g., because, although, if, when, while, since, before, after, so that).
1) Structure
| Pattern | Example | Meaning |
|---|
| Subordinating conjunction + subject + verb |
I went home because I was tired. |
Reason (why) |
| Adverbial clause + comma + main clause |
When the movie ended, we left. |
Time (when) |
| Main clause + adverbial clause |
We left when the movie ended. |
Time (when) |
2) Types of Adverbial Clauses
| Function | Common Conjunctions | Example |
|---|
| Time | when, while, before, after, until, since, as soon as | We’ll start when everyone arrives. |
| Reason / Cause | because, since, as | He stayed home because he was sick. |
| Condition | if, unless, provided (that), as long as | You can borrow my car if you drive carefully. |
| Contrast / Concession | although, even though, though, whereas, while | Although it was raining, we went hiking. |
| Purpose | so that, in order that | She whispered so that she wouldn’t wake the baby. |
| Result | so ... that; such ... that | It was so cold that the lake froze. |
| Place | where, wherever | Sit wherever you like. |
| Manner | as, as if, as though | He spoke as if he knew everything. |
| Comparison | than; as ... as | She runs faster than I do. |
3) Word Order & Punctuation
- If the adverbial clause comes first, use a comma: When the sun set, we lit the candles.
- If the main clause comes first, usually no comma: We lit the candles when the sun set.
- The subordinating conjunction already connects the ideas—don’t add another connector like and or but.
- A clause must have a subject and a verb.
4) Reduced Adverbial Clauses (Advanced)
When both clauses share the same subject, you can often reduce the adverbial clause by dropping the subject and a form of be, or by using an -ing phrase.
| Full Clause | Reduced Clause |
|---|
| While she was walking to school, she met her friend. | While walking to school, she met her friend. |
| After he finished dinner, he watched TV. | After finishing dinner, he watched TV. |
| When you are driving, be careful. | When driving, be careful. |
Only reduce the clause when the subject is the same in both parts of the sentence.
5) Common Errors
| ❌ Wrong | ✅ Correct | Why |
|---|
| He didn’t go because was tired. | He didn’t go because he was tired. | Clauses need a subject and a verb. |
| Although it was late, but we stayed. | Although it was late, we stayed. | Don’t use another connector with a subordinating conjunction. |
| When finish work, I’ll call you. | When I finish work, I’ll call you. | Add the subject; use the correct verb form. |
| Because of he was tired, he slept early. | Because he was tired, he slept early. | Because of + noun; because + clause. |
6) Summary Chart
| Function | Example | Position |
|---|
| Time | After she arrived, we had dinner. | Beginning or end |
| Reason | We stayed home because it rained. | Beginning or end |
| Condition | If it snows, school will close. | Beginning or end |
| Contrast | Although he’s young, he’s very wise. | Beginning or end |
| Purpose | She spoke quietly so that no one would hear. | Beginning or end |
| Place | Sit where you can see. | End |
| Manner | He talks as if he knows everything. | End |