Definition of conjunctions

A conjunction is a word used to connect clauses or sentences or to coordinate words in the same clause and shows the relation between them. Conjunctions make a sentence flow otherwise it will look like a list.

Kinds of conjunctions

There are three main kinds of conjunctions: correlative conjunctions, coordinating conjunctions, and subordinating conjunctions.

Correlative conjunctions

Correlative conjunctions are two parts conjunctions. They can connect either clauses or smaller grammatical units, but the structure must always be parallel. Examples of correlative conjunctions are: either … or, not only … but (also), neither … nor, both … and.

Correlative Conjunctions with clauses

Examples:
Either we should give her a raise or we should give her paid vacation. – In this situation “either … or” expresses a choice. (You have two options and you have a choice)
Not only is her boss dishonest but (also) he is temperamental. – In this example “not only … but (also)” = addition. You add more information about the subject using “not only … but (also)”.

When “not only … but (also)” joins two clauses the auxiliary is placed before the subject in the first clause only.

Correlative conjunctions with nouns

Examples:
We should give her either a raise or a vacation. – Either … or = choice) (It is incorrect to say “either we should give her a raise or a vacation.”
She got neither a raise nor a vacation. – “Neither … nor” is used to express a negative addition; “Neither … nor” is not usually used to join clauses, it is usually used to join small grammatical units.
Both Tra and her boss are stubborn. – “Both … and” = addition; “Both … and” is not used to join clauses.

Correlative conjunctions with adjectives

Example:
Her boss is not only dishonest but (also) temperamental. – Compare this example with the second given example from Correlative conjunctions with clauses – in this example “not only … but (also)” joins just simple words; adjectives.

Correlative Conjunctions with verb phrases

Example:
She neither got a raise nor took a vacation. – “Got a raise” and “took a vacation” are verb phrases. They are joined together by “neither … nor” = negative addition.

Correlative conjunctions with adverbs

Example:
Tra works both quickly and carefully. – “Both … and” = addition; joins two adverbs giving more information about how Tra works.

Additional note:
Grammarians consider better style to combine the smallest possible units using correlative conjunction. Take a look at the below examples:
Examples:
Not only have I written the article, but I have also added explanations to the examples.
I have not only written the article but also added explanations to the examples.
The above sentences express the same idea; however, the second sentence is preferred.

Coordinating conjunctions

Coordinating conjunctions with words and phrases

Some coordinating conjunctions, such as “so” and “for” can join only clauses. “Nor” usually joins clauses. Coordinating conjunctions “and”, “but”, “yet”, and “or” are often used to joins smaller parts of a sentence such as: nouns, adjectives, verbs, adverbs, and prepositional phrases.

	Examples
Nouns	Dan and Tra have met on the internet.
Adjectives	They were tired but happy.
Verb phrases	She took me to the hotel and arranged for a room.
Adverbs	Tra speaks English slowly and clearly.
Prepositional Phrases	I will visit Romania in December or at the beginning of the next year.

Coordinating conjunctions in clauses

Coordinating conjunctions are used to link two independent sentences (clauses) into one compound sentence. Coordinating Conjunctions are: and, but, for, or, so, yet, and nor. A coordinating conjunction that joins two clauses is normally preceded by a comma.

The specific coordinating conjunction used to link two sentences depends on the logical relationship between the clauses. Coordinating conjunctions used in short clauses is not preceded by comma (sometimes, not always). See the table below:

And, But, For, Or, So, Yet, and Nor
	Examples	Notes
My wife is sociable,	and she can be quite nice.	And = addition
but she has few friends.	But = contrast
for her is very secure.	For = reason
or at least she acts that way.	Or = choice
so many people like her.	So = result
yet she doesn’t like to go to parties.	Yet = contrast
My wife is not sociable. She is not very polite.	My wife is not sociable nor is she polite.	“Nor” is used to link two negative sentences. When nor begins the second clause, the auxiliary (or the verb “be”) is placed before the subject (she – in this example). The negative (“not”) in the second clause is omitted.

Subordinating Conjunctions

Subordinating conjunctions join an independent clause with a dependent clause. The subordinating conjunction is placed before the dependent clause but the dependent clause can be placed either before or after the independent clause.

Example:
Since they were bad, the kids were punished.

The dependent clause here is “they were bad” which doesn’t make sense by its own. It should be linked to an independent clause to make sense. The independent main clause is “the kids were punished”. They are joined by the subordinating conjunction ‘since’.

The most common subordinating conjunctions are: although, as, before, once, though, until, whether, etc.