Conjunctions are the "glue" of the English language. Without them, our sentences would be short, choppy, and repetitive. Effectively, they allow us to build complex ideas by linking words, phrases, or clauses.
There are three main categories of conjunctions you need to know.
1. Coordinating Conjunctions (The "FANBOYS")
These are used to connect grammatically equal elements (two nouns, two verbs, or two independent clauses).
For (Reason)
And (Addition)
Nor (Negative choice)
But (Contrast)
Or (Option)
Yet (Contrast)
So (Result)
Grammar Tip: If you are joining two independent sentences, place a comma before the conjunction.
Example: "I wanted to go for a run**, but** it started raining."
2. Subordinating Conjunctions
These start a dependent clause and link it to an independent clause. They establish a relationship of time, cause and effect, or condition.
Common examples: because, although, if, since, while, unless, whereas.
Cause/Effect: "I’m staying home because I’m tired."
Condition: "If it snows, we will go skiing."
Contrast: "Although he studied hard, he failed the exam."
Punctuation Note: If the subordinating conjunction starts the sentence, use a comma after the dependent phrase. If it’s in the middle, you usually don't need one.
3. Correlative Conjunctions
These travel in pairs. You can't use one without the other in the same sentence. They are great for showing a direct relationship between two things.

Pair	Example
Either / Or	"You can either stay or go."
Neither / Nor	"Neither the cat nor the dog was fed."
Both / And	"Both the cake and the cookies are delicious."
Not only / But also	"He is not only smart but also kind."

A Note on Conjunctive Adverbs
Words like however, therefore, moreover, and nevertheless act like conjunctions but are technically adverbs. To use them to join two sentences, you need a semicolon:
"I love coffee**; however,** it makes me jittery."