A conjunction is a word that joins two or more words, phrases, or clauses together in a sentence. There are two main types: coordinating conjunctions, which join elements of equal grammatical status, and subordinating conjunctions, which introduce a subordinate (dependent) clause. Both are essential for building complex, varied sentences at KS3.
What are coordinating conjunctions?
Coordinating conjunctions join two elements that are grammatically equal — two nouns, two phrases, or two main clauses. The most common coordinating conjunctions are remembered using the mnemonic FANBOYS:
| Letter | Conjunction | Example |
|---|---|---|
| F | For | 'She stayed home, for she was ill.' |
| A | And | 'He picked up his bag and left.' |
| N | Nor | 'She did not reply, nor did she look up.' |
| B | But | 'The task was hard, but she completed it.' |
| O | Or | 'You can stay or you can go.' |
| Y | Yet | 'He was tired, yet he continued.' |
| S | So | 'It was raining, so we stayed inside.' |
When a coordinating conjunction joins two main clauses, there should be a comma before the conjunction. This creates a compound sentence: two main clauses joined as equals.
'The door was locked, but the window was open.' ← compound sentence
What are subordinating conjunctions?
Subordinating conjunctions introduce a subordinate clause — a clause that cannot stand alone as a sentence and depends on the main clause for its meaning. Common subordinating conjunctions include:
Time: after, as, before, once, since, until, when, whenever, while
Reason/cause: because, as, since
Condition: although, even though, if, though, unless, whereas
Purpose: in order that, so that
Manner: as if, as though
When a subordinating conjunction is used, the result is a complex sentence: a main clause plus at least one subordinate clause.
'Although the door was locked, she managed to get inside.' ← the subordinate clause ('Although the door was locked') depends on the main clause ('she managed to get inside')
The subordinate clause can appear before or after the main clause:
- 'Because she was tired, she went to bed early.' (subordinate clause first — comma after it)
- 'She went to bed early because she was tired.' (subordinate clause last — no comma needed)
How do conjunctions affect sentence structure?
Conjunctions are one of the most powerful tools for varying sentence structure, which is explicitly assessed in KS3 and GCSE English writing tasks. Using only one type of conjunction — or avoiding conjunctions altogether — produces a limited and repetitive style.
| Sentence type | Structure | Conjunction type used |
|---|---|---|
| Simple | One main clause | None |
| Compound | Two main clauses of equal weight | Coordinating (FANBOYS) |
| Complex | One main clause + one subordinate clause | Subordinating |
| Compound-complex | Two main clauses + one subordinate clause | Both types |
Simple: 'The storm broke.' ← No conjunction; direct and stark.
Compound: 'The storm broke, and the lights went out.' ← Two events given equal weight.
Complex: 'Although the storm broke, the lights stayed on.' ← One event subordinated to the other; the subordination itself creates emphasis.
Compound-complex: 'Although the storm broke, the lights stayed on, and we continued working.' ← Combines both.
What are correlative conjunctions?
Correlative conjunctions are pairs of conjunctions that work together to connect parallel elements. The most common pairs are:
- either… or: 'You can either come now or wait outside.'
- neither… nor: 'She was neither angry nor afraid.'
- both… and: 'He was both talented and modest.'
- not only… but also: 'She not only finished the essay but also revised it three times.'
- whether… or: 'I do not know whether to stay or to leave.'
The elements connected by a correlative pair must be parallel in grammatical form. 'She was both talented and worked hard' is incorrect (adjective and verb) — the parallel form is 'She was both talented and hardworking' (two adjectives).
How do conjunctions affect the effect of writing?
Choosing a conjunction is not simply a grammatical decision — it carries meaning.
'And' adds without contrasting: 'She opened the box and found the letter.' The two events are presented as part of the same continuous sequence.
'But' introduces contrast or unexpected turns: 'She opened the box but found nothing.' The contrast signals disappointment or tension.
'Although' / 'even though' concede a point before overturning it: 'Although she searched everywhere, she found nothing.' The concession makes the eventual negative more emphatic.
'Because' establishes causation: 'She searched everywhere because she knew it had to be there.' The cause-and-effect structure reveals motivation.
'So' draws a consequence: 'She found nothing, so she gave up.' The conjunction makes the resignation feel logical and inevitable.
At GCSE level, a sophisticated writer chooses conjunctions for the meanings they carry, not just for grammatical correctness.
Frequently asked questions
Can a sentence start with a conjunction?
Yes — this is a common KS3 and GCSE misconception. Starting a sentence with 'But', 'And', 'Or', 'Because', or 'Although' is grammatically acceptable and often stylistically effective. 'But she was wrong.' or 'Because nothing worked.' are complete sentences in informal or literary prose. Many professional writers use sentence-initial conjunctions for dramatic effect. The restriction on starting sentences with conjunctions is a primary school rule of thumb, not a rule of grammar.
What is the difference between a conjunction and a connective?
Connective is a broader term sometimes used in schools to describe any word or phrase that connects ideas, including conjunctions ('and', 'but'), discourse markers ('firstly', 'however', 'in conclusion'), and prepositional phrases ('as a result', 'on the other hand'). A conjunction specifically refers to the grammatical word class that joins clauses. For grammar questions, use the precise term 'conjunction'; for writing advice, 'connective' often refers to the wider family of linking devices.
How many subordinating conjunctions are there?
There are several dozen in common use in English. For KS3 and GCSE, focus on the most frequent ones: because, although, while, when, since, if, unless, until, after, before, as, though, even though, whereas. Being able to use eight to ten of these fluently and correctly will give you the sentence variety that writing mark schemes reward.
Does a comma always come before a coordinating conjunction?
When a coordinating conjunction joins two main clauses, a comma before it is standard in British English: 'She arrived early, but the room was already full.' When it joins two words or short phrases — not two full clauses — no comma is needed: 'She was tired but cheerful.' The test is whether each element on either side of the conjunction could stand alone as a complete sentence. If yes, use the comma.
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