Subordinating conjunctions

On this page

• What’s a subordinating conjunction?
• How do you join clauses with a subordinating conjunction?
  • Example 1: Conjunction showing a time relationship
  • Example 2: Conjunction showing a cause-effect relationship
• What are some common subordinating conjunctions?
• How can you tell a subordinating conjunction from a preposition?
• Additional information

What’s a subordinating conjunction?

The word conjunction comes from a Latin root meaning “join.” In grammar, a conjunction is a joining word. Different types of conjunctions join words, phrases or even clauses (word groups containing a subject and a verb).

A subordinating conjunction is a type of conjunction that joins two clauses of unequal value: a subordinate (or dependent) clause and the main (or independent) clause.

As you will see below, a subordinating conjunction

• makes its own clause dependent and unable to stand alone
• shows a relationship (time, cause, condition, etc.) between the idea in its own clause and the idea in the main clause

How do you join clauses with a subordinating conjunction?

Consider these two clauses:

• Audrey lit up a cigarette.
• Henry grabbed the fire extinguisher.

These clauses are grammatically equal: they’re both independent clauses that make sense by themselves and can stand alone as sentences.

We can join these clauses into a single sentence, using a subordinating conjunction. The conjunction should be placed at the beginning of one of the clauses and should show a relationship between the ideas in the two clauses.

The examples below show how you might use different subordinating conjunctions to show two possible types of relationship between these two clauses: time and cause-effect.

Example 1: Conjunction showing a time relationship

Since the two actions seem to be happening at about the same time, we could join the clauses using a subordinating conjunction that shows a time relationship, like as or when:

• As Audrey lit up a cigarette, Henry grabbed the fire extinguisher.
• When Audrey lit up a cigarette, Henry grabbed the fire extinguisher.

Example 2: Conjunction showing a cause-effect relationship

Or, since Audrey’s smoking seems to have prompted Henry’s reaction, we could use a conjunction that shows a cause and effect relationship, like because or since:

• Because Audrey lit up a cigarette, Henry grabbed the fire extinguisher.
• Since Audrey lit up a cigarette, Henry grabbed the fire extinguisher.

What are some common subordinating conjunctions?

The table below shows some of the most common subordinating conjunctions, grouped into categories according to the relationships they express.

In the examples, the subordinate clauses are in square brackets, and the conjunctions are in bold.

How can you tell a subordinating conjunction from a preposition?

Some words that act as subordinating conjunctions (especially those expressing time) can also act as prepositions. You can tell whether they’re conjunctions or prepositions by the word group they introduce.

If they’re acting as prepositions, they introduce a phrase (a word group without a subject and verb):

• after work
• before closing time
• since our arrival
• until lunchtime

If they’re acting as subordinating conjunctions, they introduce a clause (a word group containing a subject and verb):

• after you get off work [subject: you; verb: get off]
• before the bank closes [subject: bank; verb: closes]
• since we arrived [subject: we; verb: arrived]
• until lunch is served [subject: lunch; verb: is served]

Additional information

• The section “Subordinating conjunctions” in the article "Conjunction" (HyperGrammar 2)
• Adverb clause
• Noun clause