Conjunctions

Learning Objectives

Correctly identify and use conjunctions in a sentence

Conjunctions are the words that join together sentences, phrases, and other words. Conjunctions are divided into several categories, each of which follows different rules.

Watch It

This SchoolHouse rock video on conjunctions has withstood the test of time—made in 1973, it remains relevant and entertaining today. Watch it for an overview of what conjunctions are and what they do.

You can view the transcript for “Schoolhouse Rock: Grammar- Conjunction Junction Music Video” here (opens in new window).

Coordinating Conjunctions

A compass. The most common conjunctions are and, or, and but. These are all coordinating conjunctions. Coordinating conjunctions are conjunctions that join -or coordinate- two or more equivalent items (such as words, phrases, or sentences).

The acronym FANBOYS can be used to remember the most common coordinating conjunctions: for, and, nor, but, or, yet, and so.

Examples: Coordinating Conjunctions

Here are some examples of coordinating conjunctions used in sentences:

Nuclear-powered artificial hearts proved to be complicated, bulky, and expensive. (Here, the conjunction connects three items in a list, so we need commas.)
Any external injury or internal injury puts patients at risk of uncontrolled bleeding. (Here, the conjunction connects two equivalent items but not independent clauses, so we do not use a comma.)
The current from the storage batteries can power lights, but the current for appliances must be modified within an inverter. (Here, the conjunction connects two equivalent items -independent clauses that could stand on their own – so a comma is needed).

As you can see from the examples above, a comma only appears before these conjunctions sometimes. So how can you tell if you need a comma or not? There are three general rules to help you decide.

Rule 1: Joining Two Complete Ideas

Let’s look back at one of our example sentences:

The current from the storage batteries can power lights, but the current for appliances must be modified within an inverter.

There are two complete ideas in this sentence (a complete idea has both a subject and a verb). Because each of these ideas could stand alone as a sentence, the coordinating conjunction that joins them must be preceded by a comma. Otherwise you have a run-on sentence.

Run-on sentences are one of the most common errors in college-level writing. Here’s some key information to remember:

Correct: One standalone sentence is fine, but two standalone sentences can be joined with a comma and coordinating conjunction.

Incorrect (comma splice): One standalone sentence is fine, two standalone sentences with just a comma and no coordinating conjunction is a comma splice. (The coordinating conjunction is missing here.)

Incorrect (run-on): One standalone sentence is fine two standalone sentences together with no comma and no coordinating conjunction are a run on. (We need the coordinating conjunction and the comma here!)

Rule 2: Joining Two Similar Items

What if there is only one complete idea but two subjects or two verbs? Consider the following examples:

Any external injury or internal injury puts patients at risk of uncontrolled bleeding.
In the 1960s, artificial heart devices did not fit well and tended to obstruct the flow of venous blood into the right atrium.

The first sentence has two subjects: external injury and internal injury. They are joined with the conjunction or. The second sentence has two verbs: did not fit well and tended to obstruct. They are joined with the conjunction and. We DO NOT use a comma with a coordinating conjunction when we are joining two subjects or two verbs, only when we are joining two complete ideas (or sentences that could stand on their own).

Rule 3: Joining Three or More Similar Items

What do you do if there are three or more items?

Examples: Joining 3+ items

Anna loves to run, David loves to hike, and Luz loves to dance.
Fishing, hunting, and gathering were once the only ways for people to get food.
Emanuel has a very careful schedule planned for tomorrow. He needs to work, study, exercise, eat, and clean.

As you can see in the examples above, there is a comma after each item, including the item just before the conjunction (and). There is a bit of contention about that final comma, but most styles prefer to include it (it’s called the serial comma).

Adverbial Conjunctions

Adverbial conjunctions, or conjunctive adverbs, link two separate thoughts or sentences. When used to interrupt thoughts, a comma is required on either side of the conjunction.

The first artificial hearts were made of smooth silicone rubber, which apparently caused excessive clotting and, therefore, uncontrolled bleeding.

Examples: interrupting adverbial conjunctions

Incorrect: My sister therefore, is going to be the first transgender supreme court justice.

Correct: My sister, therefore, is going to be the first transgender supreme court justice.

When used to separate complete ideas (independent clauses, which each contain a subject and a verb), a semicolon is required before the conjunction and a comma after.

The Kedeco produces 1200 watts in 17 mph winds using a 16-foot rotor; on the other hand, the Dunlite produces 2000 watts in 25 mph winds.
This is a complete sentence; however, this is also a complete sentence.

Examples

Incorrect: Mexican-Americans are described by a variety of names in the United States, for example, Latine, Chicano, and Hispanic are all terms used to describe Americans of Mexican descent. (connecting)

Correct: Mexican-Americans are described by a variety of names in the United States; for example, Latinx, Chicano, and Hispanic are all terms used to describe Americans of Mexican descent.

Be careful to think about whether the adverbial conjunction is interrupting (like therefore above) or connecting (like on the other hand or for example).

Adverbial conjunctions include the following words; however, it is important to note that this is by no means a complete list.

therefore	however	in other words
thus	then	otherwise
nevertheless	on the other hand	in fact

Correlative Conjunctions

Correlative conjunctions are word pairs that work together to join words and groups of words of equal weight in a sentence.

The table below shows some examples of correlative conjunctions used in sentences:

Correlative Conjunction	Example
either . . . or	You either do your work or prepare for a trip to the office. (Either do, or prepare)
neither . . . nor	Neither the basketball team nor the football team is doing well.
not only . . . but (also)	He is not only handsome but also brilliant. (Not only A but also B)
not only . . . but (also)	Not only is he handsome, but also he is brilliant. (Not only is he A, but also he is B)
both . . . and	Both the cross-country team and the swimming team are doing well.

Be careful! Correlative conjunctions can give you subject and verb agreement issues.

Correct: Neither the teacher nor the students are happy.

Incorrect: Neither the teachers nor the student are happy.

The verb m matches the closest the subject. We reviewed this in the Verbs section.

Subordinating Conjunctions

Subordinating conjunctions are conjunctions that join an independent clause and a dependent clause. The most common subordinating conjunctions in the English language are shown in the table below:

after	although	as	as far as	as if	as long as	as soon as
as though	because	before	even if	even though	every time	if
in order that	since	so	so that	than	though	unless
until	when	whenever	where	whereas	wherever	while

Examples: Subordinating conjunctions

Here are some examples of subordinating conjunctions:

The heart undergoes two cardiac cycle periods: diastole, when blood enters the ventricles, and systole, when the ventricles contract and blood is pumped out of the heart.
Whenever an electron acquires enough energy to leave its orbit, the atom is positively charged.
She did the favor so that he would owe her one.

Let’s take a step back and look for a pattern in comma usage. Commas aren’t based on whether a subordinating conjunction is present—they depend on the placement of the clauses.

Some clauses add extra information that isn’t necessary for the main meaning of the sentence. These nonessential clauses need commas to separate them from the rest of the sentence.

Example: Nonessential clauses

Example: The heart undergoes two cardiac cycle periods: diastole, when blood enters the ventricles, and systole, when the ventricles contract and blood is pumped out of the heart.

Without extra information: The heart undergoes two cardiac cycle periods: diastole and systole.

In the first sentence, the extra details about when blood enters and exits the heart are helpful but not essential. That’s why they’re set off with commas.

A dependent clause cannot stand alone as a full sentence, while an independent clause can.

Examples: Dependent and independent clauses

Example: Whenever an electron acquires enough energy to leave its orbit, the atom is positively charged.

As seen in the example above, when a dependent clause comes before an independent clause, it should be followed by a comma.

A complete sentence (Independent clause): The atom is positively charged.
Not a complete sentence (Dependent clause): Whenever an electron acquires enough energy to leave its orbit.

If a dependent clause follows an independent clause, no comma is needed.

Example (No Comma Needed): She did the favor so that he would owe her one.

But if the dependent clause comes first, you do use a comma:

Example (Comma Needed): So that he would owe her one, she did the favor.

Key Takeaway: Comma usage and placement

Dependent clause first → Use a comma

Whenever an electron acquires enough energy to leave its orbit, the atom is positively charged.

Dependent clause after → No comma

She did the favor so that he would owe her one.

Extra (nonessential) information → Use commas on both sides

The heart undergoes two cardiac cycle periods: diastole, when blood enters the ventricles, and systole, when the ventricles contract and blood is pumped out of the heart.

Watch IT

If you feel like you need some additional help understanding the difference between independent and dependent clauses (which is key to using subordinating conjunctions), check out this video.

You can view the transcript for “Subordinating Conjunctions” here (opens in new window).

Try It

Explain Answers

Here are the sentences with suggested conjunctions. These are not the only possible solutions. If you answered something different, compare your reasoning with the explanation provided below.

Karni’s roommate, Joana, decided to drive to work; therefore, Karni rode into the city with her.
- As the punctuation currently exists (a semicolon followed by a comma), the sentence needs an adverbial conjunction. However, using therefore here feels a little stuffy. If you change the semicolon to a comma and remove the second comma, you can then use the coordinating conjunction so instead, which feels more natural: “. . . , so Karni rode into the city with her.”
They needed to turn left on 140th Street, but that street was under construction.
- Since the blank is preceded by a comma, a coordinating conjunction should go here. The conjunction but has the most appropriate meaning in this sentence.
Before Karni could say anything, however, Joana had already found an alternate route.
- Since there is no comma after the first blank, we know we need a subordinating conjunction here. Before makes the most sense here.
- Since this blank appears in the middle of an idea, we know we need an adverbial conjunction here. However makes the most sense.
No sooner did Karni arrive at work than her boss told her she would be working with her coworker Ian on her next project.
- The two blanks in this sentence indicate a correlative conjunction. The sentence indicates the two things happened at the same time, so no sooner . . . than is the correct option here.
Karni was really impressed by Ian’s professional accomplishments, but she was anxious about working with him.
- Since the blank is preceded by a comma, a coordinating conjunction should go here. The conjunction but has the most appropriate meaning in this sentence.
Karni thought Ian was annoying, unpredictable, and reckless.
- Since the blank is preceded by a comma, a coordinating conjunction should go here. The conjunction and has the most appropriate meaning in this sentence.
However, Karni was willing to put aside her opinions to get the job done.
- Since the blank is followed by a comma, we know we need an adverbial conjunction here. However makes the sense here.
She knew Ian would put in his best effort while they worked together, so she felt she could do no less—even if he frustrated her.
- Since there is no comma before or after the first blank, we know we need a subordinating conjunction here. While makes the most sense here, but as long as or if would also work.
- Since the blank is preceded by a comma, a coordinating conjunction should go here. The conjunction so has the most appropriate meaning in this sentence.
- This blank is a little trickier; it is preceded by a dash, which can stand in for a lot of different punctuation marks. A subordinating conjunction is likely the best solution. We’ve used even if here, but there are a lot of possibilities, including even though.
Personal relationships are often as important as professional skills.
- The two blanks in this sentence indicate a correlative conjunction. The sentence indicates two things of equal importance, so as . . . as is the correct option here.

Module 12: Grammar Basics