Subordinating Conjunctions
Subordinating conjunctions connect a dependent (subordinate) clause to a main clause. Unlike coordinating conjunctions, they make one clause depend on the other — creating a relationship of time, cause, condition, contrast, or purpose.
What are subordinating conjunctions?
A subordinating conjunction introduces a subordinate clause — a clause that cannot stand alone as a complete sentence. The subordinate clause depends on the main clause for its meaning.
She left [main] because she was tired [subordinate].
Although it was raining [subordinate], we went out [main].
Common subordinating conjunctions by meaning
| Meaning | Conjunctions | Example |
|---|---|---|
| Time | when, while, after, before, since, until, as, once, as soon as | Call me when you arrive. |
| Cause / Reason | because, since, as, now that | She stayed because she wanted to help. |
| Condition | if, unless, provided that, as long as, in case | I'll go if you come with me. |
| Contrast | although, though, even though, whereas, while | Although it was cold, we enjoyed it. |
| Purpose | so that, in order that | She left early so that she wouldn't be late. |
| Result | so…that, such…that | It was so hot that we went swimming. |
| Comparison | than, as…as | She runs faster than I do. |
Clause order and commas
The subordinate clause can come before or after the main clause.
- When the subordinate clause comes first, use a comma after it.
- When the main clause comes first, no comma is usually needed.
Because it was raining, we stayed home. (subordinate first → comma)
We stayed home because it was raining. (main first → no comma)
Although she was tired, she kept working.
She kept working although she was tired.
because vs. since vs. as
All three can express cause, but they have different emphasis. Because gives the strongest, most direct reason. Since and as imply the reason is already known or obvious, and are softer in tone.
I left early because I had a meeting. (direct reason)
Since everyone is here, let's begin. (known fact → softer)
As it was getting late, we said goodbye. (contextual / narrative)
unless = if … not
Unless introduces a condition that, if not met, produces a result. It means "except if".
Unless you study, you won't pass. (= If you don't study, you won't pass.)
Common mistake: A subordinate clause on its own is a sentence fragment. ✗ Although she was tired. → ✓ Although she was tired, she finished the work.
Tip: While and whereas can both show contrast, but whereas is stronger — it highlights a clear, direct opposition between two facts: I like coffee, whereas she prefers tea.