Conjunctions in English: types, rules, and examples

Conjunctions connect words, groups of words, or entire clauses to build fluent sentences and express logical relationships: addition, contrast, cause, condition. English distinguishes three main families, each with its own punctuation rules. This guide details the complete lists, usage rules, and the most common pitfalls.

Coordinating conjunctions: FANBOYS

Coordinating conjunctions connect two elements of equal grammatical status: two words, two groups of words, or two independent clauses. English has seven of them, remembered by the mnemonic acronym FANBOYS.

When a coordinating conjunction connects two independent clauses, a comma is placed before it: I wanted to go to the movies, but it was raining. If it simply connects two words or groups of words, the comma disappears: She likes tea and coffee.

Subordinating conjunctions

A subordinating conjunction introduces a dependent clause, which cannot form a complete sentence on its own, and connects it to an independent main clause. It specifies a relationship of time, cause, condition, or contrast.

A practical mnemonic to remember a wide range of these conjunctions is the phrase ON A WHITE BUS, where each letter refers to one of the most common ones.

Punctuation depends on the position of the subordinate clause. If it comes before the main clause, a comma separates the two: Although it was raining, we went for a walk. If the main clause comes first, no comma is needed: We went for a walk although it was raining.

Correlative conjunctions (pairs)

Correlative conjunctions always work in pairs and connect grammatically equivalent elements. They require a parallel structure: the two connected elements must take the same grammatical form.

With either…or and neither…nor, the word order can be inverted at the beginning of a sentence, causing a subject-auxiliary inversion, as in a question.

Conjunctive adverbs: a common trap

Words like however, therefore, thus, meanwhile, consequently, nevertheless look like conjunctions but are not: they are conjunctive adverbs. They connect two ideas between two clauses, but their punctuation differs fundamentally from that of a coordinating conjunction.

• It was raining; therefore, I decided not to go to the beach.

The rule is fixed: semicolon before, comma after. Confusing but (coordinating conjunction, no semicolon required) and however (conjunctive adverb, semicolon required) is one of the most frequent punctuation errors among learners.

Because vs because of: conjunction or preposition?

Frequent error: confusing because, a subordinating conjunction always followed by a complete clause (subject + verb), with because of, a prepositional phrase always followed by a noun or noun phrase, never a clause.

• We stayed home because it was raining. → because + clause (it was raining).
• We stayed home because of the rain. → because of + noun (the rain).

The most common confusion is writing because of it was raining, mixing the two constructions.

The multiple uses of as

As is one of the most versatile conjunctions in English: depending on the context, it expresses time, cause, or comparison, three meanings that should not be confused.

The so…that and such…that structures

These two correlative structures express a consequence, but their grammatical construction differs depending on what follows: so precedes an adjective or adverb alone, while such precedes a noun phrase (with or without an adjective).

• The film was so boring that I fell asleep. → so + adjective alone.
• It was such a boring film that I fell asleep. → such + noun phrase (a boring film).

The rule concerns the nature of the word that immediately follows, not the overall meaning of the sentence, which explains the frequent error it was so a boring film.

Purpose: in order that and so that

To express a purpose, two subordinating conjunctions introduce an entire clause (unlike in order to, followed by an infinitive): in order that, more formal, and so that, more common in speech.

• She studied hard so that she could pass the exam. → Elle a beaucoup travaillé pour pouvoir réussir l’examen.
• The company changed its policy in order that all employees would be treated fairly.

Extended list of conjunctive adverbs

Beyond however and therefore, a larger family of conjunctive adverbs allows you to nuance a logical relationship between two clauses, always with the same punctuation (semicolon before, comma after).

These adverbs can also start a separate sentence, preceded by a period (not a semicolon): The plan was risky. However, it worked. Both punctuations are correct; the choice depends on the desired degree of closeness between the two ideas.

The comma with correlatives connecting two clauses

When a correlative pair connects two complete independent clauses (not just two simple words), a comma is inserted before the second part of the pair, just like with a classic coordinating conjunction.

• Not only did she finish the marathon, but she also broke the record.
• Either you apologize, or I’m leaving.

Conversely, when the pair connects two simple words, the comma disappears: Either tea or coffee works for me.

Do not confuse: than/then, unless/until, but/however

Starting a sentence with a conjunction

Starting a sentence with but, and or so remains grammatically correct, even if it sometimes sounds less natural. This usage is accepted in speech and informal writing, but generally avoided in an academic or formal register.

• But I still don’t understand why we have to go.
• So, let’s discuss this further before making a decision.

Be careful, however, never to leave a subordinate clause alone, without a main clause: Although the clouds were dark is not a complete sentence and must be followed by its logical complement: Although the clouds were dark, we still decided to go for a walk.

Practical exercise

Check your knowledge of English conjunctions: