What do conjunctions do in sentences?

Conjunctions: the little glue that keeps ideas from feeling apart

If you’ve ever reread a sentence and felt something just… fits, you’ve encountered a conjunction at work. These tiny words are not flashy, but they’re essential. They’re the connectors that keep thoughts from sliding into chaos and help a reader follow a line of reasoning without getting tangled.

What do conjunctions actually do?

Here’s the thing: the function of conjunctions is to connect words, phrases, or clauses. They’re the linking words that tie different parts of a sentence together, creating coherence. Without them, your writing would feel choppy, like a string of stand-alone ideas instead of a single, flowing thought.

Think of it this way: you don’t want your sentences to be a bunch of isolated Lego bricks; you want them to snap together into a wall that someone can lean against. Conjunctions are the studs that lock those bricks in place.

A quick tour of the big kinds

There are a few main flavors, and each one helps you shape your sentence in a slightly different way.

1. Coordinating conjunctions: the “glue” that joins equal pieces

These link words, phrases, or short clauses of roughly the same weight. The classic list is the FANBOYS: for, and, nor, but, or, yet, so. Here are some simple examples:

• I wanted to go for a run, but it started raining.

• She can watch a movie, or she can read a book.

• He finished early, and he treated himself to dessert.

Because coordinating conjunctions connect equal parts, they’re perfect for building compound sentences. They keep ideas balanced and give you a steady rhythm, especially when you want to show balance, contrast, or choice.

2. Subordinating conjunctions: linking the main idea to a dependent idea

These are the big starters that introduce a dependent clause: because, since, although, while, when, if, unless, and many more. They’re like archways in a sentence: they set up a relationship between the main clause and something that isn’t complete on its own.

• Because the streets were slick, we walked slowly.

• Although he was tired, he finished the report.

• If you’re unsure, ask a clarifying question.

Subordinating conjunctions help you explain cause and effect, contrast, time, condition, and more. They’re how you show how one idea depends on another.

3. Correlative conjunctions: a matching pair that tightens the bond

These come in pairs and show you two elements that work together. Common pairs are either… or, neither… nor, not only… but also, both… and.

• Not only does she love poetry, but she also writes it.

• Either you start now, or you’ll miss the deadline.

• Both the professor and the students agreed on the plan.

Correlative conjunctions are handy when you want to emphasize a relationship between two ideas, with a bit of symmetry.

Why conjunctions matter for clarity and flow

Conjunctions aren’t just ornamental. They guide a reader’s attention and shape how a sentence lands. A well-placed conjunction can:

• Show relationships clearly: cause-and-effect, comparison, or condition. When you say “because,” the reader expects a reason; when you say “if,” they anticipate a condition.

• Control rhythm: short sentences with a single conjunction in the middle keep pace; stacking longer clauses with “and” or “but” can build momentum.

• Help you avoid run-ons: without a clear connector, a string of ideas can feel like a jumble. Conjunctions help you pause, reflect, and move on to the next thought smoothly.

• Create nuance: “but” signals contrast; “yet” hints a softer counterpoint; “so” signals a consequence. The same sentence idea can feel very different depending on the conjunction you choose.

A few everyday touches

Conjunctions show up in everyday speech as well, which is a good reminder that good writing often mirrors natural language. You’ll hear people say:

• “I’d love to come, but I’m packed.” (contrast with a plan)

• “We can go now, or we can wait.” (choice)

• “He didn’t just finish the project; he nailed it.” (emphasis with not only…but also)

These little moments translate nicely to writing because they reflect how people make sense of ideas in real time.

Common pitfalls to avoid (and how to fix them)

No one wants stiff, awkward sentences, and a few puny missteps with conjunctions can do a lot of damage. Here are some friendly cautions and fixes:

• Mixing up clauses: If you start with a dependent clause, make sure the main clause follows in a way that makes sense.

Example fix: Because the rain was heavy, we postponed the hike. We found a cozy cafe instead. (The main idea follows the dependent clause logically.)

• The dreaded comma splice: connecting two independent clauses with just a comma usually isn’t enough. You want a semicolon, a coordinating conjunction, or break it into two sentences.

Poor: It was getting late, we decided to head home.

Better: It was getting late, so we decided to head home.

Or: It was getting late; we decided to head home.

• Overusing “and” to cram too much in one sentence: variety is your friend. Mix in a subordinate clause or a correlative pair when you want to deepen meaning without lengthening the sentence excessively.

• Starting every sentence with a conjunction: starting sentences with “and” or “but” can sound conversational, which isn’t always wrong. Just use it purposefully to create a flow or a pause, not out of habit.

Tips for using conjunctions well in your writing

• Plan the relationship first: before you choose a conjunction, be clear about how you want two ideas to relate. Is it cause and effect? Is it a contrast? Time or condition?

• Use punctuation as a guide: in a compound sentence, a comma plus a coordinating conjunction is common. If you’re combining two independent clauses with a semicolon, you don’t need a conjunction at all.

• Read aloud to feel the rhythm: if a sentence trips when you read it, a different conjunction or punctuation choice might help.

• Mix it up: don’t rely on the same few conjunctions every time. Let your ideas lead the choice.

• Keep it natural: choose a conjunction that matches how you’d explain the idea in speech. The goal is clarity, not cleverness for its own sake.

A practical example you can dissect

Let’s break down a short paragraph to see how conjunctions knit ideas together:

Learning about how conjunctions work is a bit like learning to listen well. When you hear how speakers connect thoughts—whether in a chat with a friend or a TED Talk—you start to notice the patterns. Not only does this awareness improve your writing, but it also helps you edit more efficiently. If you catch a sentence where the relationship between ideas isn’t clear, you can swap a word or two to make the connection obvious.

In this example, you can see how coordinating, subordinating, and correlative conjunctions all play a role. The sentence “Not only does this awareness improve your writing, but it also helps you edit more efficiently” uses not only… but also to emphasize two linked benefits. The clause “If you catch a sentence where the relationship between ideas isn’t clear” uses a subordinating conjunction (if) to set up a condition. And “When you hear how speakers connect thoughts” uses when to ground the idea in time.

Reading, listening, and noticing

If you want to get better at using conjunctions, tune your ear to how real writers and speakers use them. Read a variety of texts—articles, essays, even scripts—and note where a conjunction helps the sentence breathe or where a mismatch makes the idea stumble. You’ll start to see patterns: where to place a clause for emphasis, how to signal a contrast, and when a pair of ideas will feel most natural with a correlative setup.

Subtle digressions that still circle back

Conjunctions pop up outside formal writing, too. In emails, you’ll often see a brisk “I’m free Friday, but not Thursday.” In blogs, a well-placed “however” or “therefore” can keep readers from losing the thread. Even in speech, we use them to steer conversations, to show we’re following someone else’s line of thought, or to pivot when the topic shifts.

A practical takeaway

If you want sharper writing, pay attention to how you link ideas. Conjunctions are the cogs that keep a sentence turning. Start with a clear idea you want to express, decide how it relates to the next idea, and pick the conjunction that makes that relationship obvious. Then polish the sentence so it reads as smoothly as a conversation you’d enjoy having in person.

Final reflection: the quiet power of connection

Conjunctions may be small, but they carry a big job. They don’t just glue words together; they shape meaning, guide tempo, and help readers follow your thoughts with ease. Whether you’re drafting a quick note, a thoughtful paragraph, or a longer piece, treating conjunctions as the deliberate tools they are will elevate your writing. So next time you sit down with a sentence, ask yourself: what relationship do I want to reveal here, and which conjunction will let that relationship shine?

If you enjoyed this exploration, you’ll notice the same logic at work across all kinds of English writing—news reports, essays, or even a clever social post. The goal isn’t about cleverness for its own sake; it’s about clarity, flow, and connection. And that, after all, is what makes every sentence feel a little bit more alive.