Using Conjunctions | Definition, Rules & Examples
A conjunction is a word that is used to connect words, phrases, and clauses. There are many conjunctions in the English language, but some common ones include and, or, but, because, for, if, and when.
There are three basic types of conjunctions: coordinating, subordinating, and correlative.
This type of conjunction is used to connect items that are grammatically equal: two words, two phrases, or two independent clauses. There are seven coordinating conjunctions in English, and you can remember them using the mnemonic device FANBOYS: for, and, nor, but, or, yet, so.
A conjunction of this type is placed between the items that it links together.
Coordinating conjunctions can join two nouns, verbs, adjectives, or other types of word.
- The data was gathered through questionnaires and interviews.
- I don’t like to run or swim.
- He was clever but lazy.
They can also join different types of phrases.
- The dog wagged his tail and panted excitedly.
- The results were undeniably intriguing yet ultimately inconclusive.
- She usually studies in the library or at a cafe.
A clause is a group of words that contains at least a subject and a verb. An independent clause can stand on its own as a full sentence, expressing a complete thought.
- Today Jane Austen is one of the most widely read English novelists, but she achieved little fame during her lifetime.
In the sentence above, the coordinating conjunction but creates a relationship between two independent clauses. Therefore, you place a comma before but. Notice that the two clauses also work as sentences on their own.
- Today Jane Austen is one of the most widely read English novelists. She achieved little fame during her lifetime.
Punctuating coordinating conjunctions
When joining two words or phrases with a coordinating conjunction, do not use a comma.
|Data was gathered through questionnaires, and interviews.
|Data was gathered through questionnaires and interviews.
|She usually studies in the library, or at a cafe.
|She usually studies in the library or at a cafe.
In these examples, the conjunction joins two words or phrases that are connected to a single verb (gathered and studies), so you shouldn’t place a comma before and.
When joining two independent clauses, however, use a comma before the conjunction.
|Data was gathered through questionnaires and selected respondents participated in interviews.
|Data was gathered through questionnaires, and selected respondents participated in interviews.
|She usually studies in the library but when it is too busy she goes to a cafe.
|She usually studies in the library, but when it is too busy she goes to a cafe.
In these examples, the clauses before and after the conjunction could both stand as full sentences on their own, so a comma is required.
This type of conjunction includes words like because, if, although, since, until, and while. A subordinating conjunction is used to introduce a dependent clause.
In contrast to an independent clause, a dependent clause (also known as a subordinate clause) is a group of words that contains a subject and a verb but cannot stand as a complete sentence on its own. A dependent clause does not express a complete idea, so it must always be attached to an independent clause.
- Because I woke up late this morning. I went to school without eating breakfast.
- Because I woke up late this morning, I went to school without eating breakfast.
- I went to school without eating breakfast because I woke up late this morning.
I woke up late this morning is an independent clause, but the subordinating conjunction because turns it into a dependent clause: Because I woke up late this morning does not finish a complete thought. It must be joined to an independent clause to form a grammatically correct sentence.
The subordinating conjunction defines the relationship between the clauses. The table below shows some common subordinating conjunctions and the relationships they express, but note that this is not a complete list.
|Common subordinating conjunctions
|Cause and effect
|because, since, as
|when, before, after, once, until, whenever, since, while
|if, unless, in case
|although, though, whereas
Punctuating subordinating conjunctions
When a subordinating conjunction follows an independent clause, a comma is often not necessary. In general, when the dependent clause contains essential information about the independent clause, don’t use a comma.
|She will receive a major bonus, if she succeeds in closing the corporate partnership deal.
|She will receive a major bonus if she succeeds in closing the corporate partnership deal.
|John’s friends snuck into his apartment to set up a surprise party, while he was at work.
|John’s friends snuck into his apartment to set up a surprise party while he was at work.
However, when the subordinating conjunction comes at the beginning of the sentence, use a comma at the end of the dependent clause.
|If she succeeds in closing the corporate partnership deal she will receive a major bonus.
|If she succeeds in closing the corporate partnership deal, she will receive a major bonus.
|While John was at work his friends snuck into his apartment to set up a surprise party.
|While John was at work, his friends snuck into his apartment to set up a surprise party.
This type of conjunction always comes in a pair and is used to join grammatically equal elements in a sentence. Common pairs include either … or, neither … nor, not only … but also, and both … and. In most cases, no comma should be used between the two elements.
- Her book on the Vietnam War drew not only from interviews with other survivors but also from her own experiences in the conflict.
Correlative conjunctions must use parallel structure, which means the two elements should take the same grammatical form.
- She planned to collect data by either using an online survey or phone interviews.
- She planned to collect data by either using an online survey or conducting phone interviews.
Starting a sentence with a conjunction
Beginner writers are often taught that sentences should not begin with a coordinating conjunction. However, it is not strictly incorrect to begin a sentence with a conjunction, and you may find it used effectively by skilled writers to create emphasis.
While such usage has become acceptable in popular and literary language, it is generally best avoided in academic writing where possible.
A subordinating conjunction can come at the start of a sentence, but only if the dependent clause is followed by an independent clause.
A dependent clause on its own is known as a sentence fragment.
Although fragments are often used in speech and informal writing, they should generally be avoided in academic writing.
Sources for this article
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