Conjunctions are the words that join sentences, phrases, and other words together. Conjunctions are divided into several categories, all of which follow different rules. We will discuss coordinating conjunctions, adverbial conjunctions, correlative conjunctions, and subordinating conjunctions.
Coordinating Conjunctions
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 mnemonic acronym FANBOYS can be used to remember the most common coordinating conjunctions: for, and, nor, but, or, yet, and so.
- For: presents a reason (“They do not gamble or smoke, for they are ascetics.”)
- And: presents non-contrasting items or ideas (“They gamble, and they smoke.”)
- Nor: presents a non-contrasting negative idea (“They do not gamble, nor do they smoke.”)
- But: presents a contrast or exception (“They gamble, but they don’t smoke.”)
- Or: presents an alternative item or idea (“Every day they gamble, or they smoke.”)
- Yet: presents a contrast or exception (“They gamble, yet they don’t smoke.”)
- So: presents a consequence (“He gambled well last night, so he smoked a cigar to celebrate.”)
Here are some examples of these used in sentences:
- Nuclear-powered artificial hearts proved to be complicated, bulky, and expensive.
- In the 1960s, artificial heart devices did not fit well and tended to obstruct the flow of venous blood into the right atrium.
- The blood vessels leading to the device tended to kink, obstructing the filling of the chambers and resulting in inadequate output.
- Any external injury or internal injury put patients at risk of uncontrolled bleeding because the small clots that formed throughout the circulatory system used up so much of the clotting factor.
- The current from the storage batteries can power lights, but the current for appliances must be modified within an inverter.
Practice
Are the correct coordinating conjunctions being used in each of the following sentences? Explain your reasoning why or why not:
- I love boxing or sewing. They’re both a lot of fun.
- Martin is pretty good at writing, for Jaden is better.
- Juana had to choose. Would she join the red team and the blue team?
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 (a noun or pronoun) and a verb. The subjects have been italicized, and the verbs bolded:
- The current from the storage batteries can power lights.
- The current for appliances must be modified within an inverter.
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’ll have a run-on sentence.
Rule 2: Joining Two Similar Items
So what if there’s only one complete idea, but two subjects or two verbs?
- Any external injury or internal injury put patients at risk of uncontrolled bleeding because the small clots that formed throughout the circulatory system used up so much of the clotting factor.
- This sentence has two subjects: external injury and internal injury. They are joined with the conjunction and; we don’t need any additional punctuation here.
- In the 1960s, artificial heart devices did not fit well and tended to obstruct the flow of venous blood into the right atrium.
- This sentence has two verbs: did not fit well and tended to obstruct. They are joined with the conjunction and; we don’t need any additional punctuation here.
Rule 3: Joining Three or More Similar Items
What do you do if there are three or more 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 do 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 prior to the conjunction. There is a little bit of contention about this, but overall, most styles prefer to keep the additional comma (also called the serial comma). We discuss the serial comma in more depth in Text: Commas.
Starting a Sentence
Many students are taught—and some style guides maintain—that English sentences should not start with coordinating conjunctions.
This video shows that this idea is not actually a rule. And it provides some background for why so many people may have adopted this writing convention:
Practice
In this practice, you will combine multiple sentences into a single sentence. For example, look at the sentences “Clint was very skilled at his job. Wade was very skilled at his job.” You would combine these two sentences into something like this, using coordinating conjunctions:
- Clint and Wade were both very skilled at their jobs.
- Clint was very skilled at his job, and Wade was too.
When you combine sentences, you can remove repeated information. As you complete this exercise, type your answers in the text frame below.
- Wade was really impressed by Clint. Wade was anxious about working with him.
- Clint thought Wade was annoying. Clint thought Wade was unpredictable. Clint thought Wade was possibly dangerous.
- In the end, Clint worked well with Wade. In the end, Wade worked well with Clint.
Adverbial Conjunctions
Adverbial conjunctions link two separate thoughts or sentences. When used to separate thoughts, as in the example below, 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.
When used to separate complete ideas (items with both a subject and a verb), as in the examples below, 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.
- For short periods, the fibers were beneficial; however, the eventual buildup of fibrin on the inner surface of the device would impair its function.
- The atria of the heart contribute a negligible amount of energy; in fact, the total power output of the heart is only about 2.5 watts.
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 |
Practice
Fill in the missing punctuation marks for the sentences below. Type the corrected sentences in the text frame below:
- My roommate decided to drive to work __ therefore __ I decided to get a ride with her.
- We needed to turn left on 140th Street. That street __ however __ was under construction.
- In other words __ we couldn’t turn on the street we needed to.
Correlative Conjunctions
Correlative conjunctions are word pairs that work together to join words and groups of words of equal weight in a sentence. This video will define this types of conjunction before it goes through five of the most common correlative conjunctions:
The table below shows some examples of correlative conjunctions being used in a sentence:
| 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 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. |
| whether…or | You must decide whether you stay or you go. (It’s up to you) |
| Whether you stay or you go, the film must start at 8 pm. (It’s not up to you) | |
| just as…so | Just as many Americans love basketball, so many Canadians love ice hockey. |
| as much…as | Football is as much an addiction as it is a sport. |
| no sooner…than | No sooner did she learn to ski, than the snow began to thaw. |
| rather…than | I would rather swim than surf. |
| the…the | The more you practice dribbling, the better you will be at it. |
| as…as | Football is as fast as hockey (is (fast)). |
Practice
Re-write the following items. Your new sentences should use correlative conjunctions. Type your revisions in the text frame below:
- She finished packing right when the moving truck showed up.
- There are two shifts you can work: Thursday night or Saturday afternoon.
- Chemistry and physics are both complex.
Subordinating Conjunctions
Subordinating conjunctions, are conjunctions that join an independent clause and a dependent clause. 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.
- If the wire is broken, electrons will cease to flow and current is zero.
- I’ll be here as long as it takes for you to finish.
- She did the favor so that he would owe her one.
Let’s take a moment to look back at the previous examples. Can you see the pattern in comma usage? The commas aren’t dependent on the presence subordinating conjunctions—they’re dependent on the placement of clauses they’re in. Let’s revisit a couple examples and see if we can figure out the exact rules:
- 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.
- These clauses are both extra information: information that is good to know, but not necessary for the meaning of the sentence. This means they need commas on either side.
- Whenever an electron acquires enough energy to leave its orbit, the atom is positively charged.
- In this sentence, the dependent clause comes before an independent clause. This means it should be followed by a comma.
- She did the favor so that he would owe her one.
- In this sentence, the independent clause comes before an dependent clause. This means no comma is required.
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 |
Practice
All of the commas have been removed from the following passage. Re-type the passage in the text frame below, adding in the correct punctuation. Identify all of the subordinating conjunctions as well.
Thales came to the silent auction in order to win the chance to be drawn by his favorite artist. Before anyone else could bid Thales went to the bidding sheet and placed an aggressive bid. He knew he would have to come back and check on it while the auction was still open but he felt confident in his ability to win. He was determined to win the auction even if it took all of his money to do so.