PUNCTUATING THE CO-ORDINATING CONJUNCTION IN
SIMPLE COMPOUND SENTENCES
In this module, you will learn to use
 Comma punctuation with co-ordinating conjunctions
 Semicolon punctuation with co-ordinating conjunctions
 Semicolon punctuation without conjunctions.
Introduction
Using the co-ordinating conjunction, we are going to punctuate independent clauses in
simple compound sentences--sentences containing two independent clauses. We'll look at
a rule and at a variation of that rule; then we'll look at joining independent clauses without
using any conjunctions.
The seven co-ordinating conjunctions are and, but, for, or, nor, yet, and so.
Punctuation
We use co-ordinating conjunctions to join ideas of equal value--co-ordinate ideas.
Co-ordinating Conjunction Rule
When using a co-ordinating conjunction to join two independent clauses, place a comma
before the conjunction.
Insert the required punctuation into the following sentences. If no punctuation is required,
consider the sentence to be one independent clause.
Sentence:
"I did my homework last night but I forgot to bring it to school."
1. Identify the first clause.
We identify "I did my homework last night."
2. Label that clause as dep (dependent) or indep (independent).
The clause does not start with a subordinating conjunction, so the clause is independent.
3. We label the clause indep.
The sentence now looks like this:
Indep
I did my homework last night but I forgot to bring it to school.
4. Identify the second clause.
We identify "but I forgot to bring it to school."
5. Label that clause as dep or indep.
The clause does not start with a subordinating conjunction, so the clause is independent.
We label the clause indep.
The sentence now looks like this:
Indep
"I did my homework last night
Indep
but I forgot to bring it to school."
We have a punctuation problem involving independent clauses. We recognize that the two
independent clauses are joined with a co-ordinating conjunction. So we apply the coordinating conjunction punctuation rule.
"I did my homework last night , but I forgot to bring it to school."
As we can see, the pattern for the above sentence is
Independent , co-ordinating conjunction independent.
Another Sentence:
"The ambulance raced down the street and stopped just in time."
We identify "raced" and "stopped" as verbs and "ambulance" as the lone subject. The
conjunction "and" joins two verbs not two clauses. We have one independent clause with a
compound verb.
The pattern for the above sentence is
Independent clause (no punctuation required).
So ensure you actually have two clauses before you start punctuating co-ordinating
conjunctions.
Co-ordinating Conjunction Exception
If either independent clause contains two or more commas or if the clauses are very long,
change the comma in front of the co-ordinating conjunction into a semicolon.
Sentence:
"Sometimes, natural, unfiltered light is sufficient but artificial light is a good supplement."
We have a punctuation problem involving independent clauses. We recognize the coordinating conjunction "but." So we apply the co-ordinating conjunction punctuation rule.
The sentence now looks like this:
Indep
Sometimes, natural, unfiltered light is sufficient
,
Indep
but artificial light is a good supplement.
We find two commas in the first clause. So we change the comma in front of "but" into a
semicolon.
Sometimes, natural, unfiltered light is sufficient ; but artificial light is a good supplement.
The pattern for the above sentence is
independent ; co-ordinating conjunction independent.
There are times when we wish to connect equal ideas and yet show a very casual--a very
limited--relationship. To show this kind of casual relationship, we use the bare semicolon.
The Bare Semicolon Rule
To join two independent clauses without using a conjunction, use a semicolon alone as
punctuation. Here's an example:
Clauses:
"the sun slowly lightens the eastern sky
the sheep stir sleepily"
We show this casual relationship by punctuating as follows:
The sun slowly lightens the eastern sky ; the sheep stir sleepily.
The pattern for the above sentence is
independent ; independent.
Technical and business writers use this bare semicolon punctuation sparingly. We use it
sparingly because in technical writing when we join two independent clauses, we generally
want to show a definite relationship between the two ideas.
Review
When using a co-ordinating conjunction to join two independent clauses, place a comma
before the conjunction.
If either independent clause contains two or more commas or if the clauses are very long,
change the comma in front of the co-ordinating conjunction into a semicolon.
To join two independent clauses without using a conjunction, use a semicolon alone as
punctuation.
Exercises
For the first nine questions, select the answer that shows the clause structure and the
comma/semicolon punctuation required for the sentence. The answers appear after the
last question.
1. The bus first veered around the corner and then the bus careened against the guard
rail.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
2. We were having a great deal of fun but we started home at the specified time.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
3. We were having a great deal of fun we hated to leave at the specified time.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
4. Our candidate was leading by a large margin yet he continued to look worried.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
5. By 4 p.m., our candidate, Harry Doyle, was leading by a large margin yet, to
everyone's amazement, he continued to look worried.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
6. The elderly lady did not see the car nor did she hear the horn.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
7. The elderly lady did not see the car nor hear the horn.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
8. We still have a few hours to ski before sunset so we can have another few runs.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
9. We still have a few hours to ski before sunset so we can have another few runs, Sally,
our team leader, suggested eagerly.
A. Independent clause (no additional punctuation required)
B. Independent ; independent
C. Independent , co-ordinating conjunction independent
D. Independent ; co-ordinating conjunction independent
For the next six questions, select the correctly punctuated sentence.
10.
A. We made our reservations and immediately packed our bags.
B. We made our reservations, and immediately packed our bags.
C. We made our reservations; and immediately packed our bags.
11.
A. This is where I live, I love this neighbourhood.
B. I love this neighbourhood, so this is where I live.
C. I love this neighbourhood; so this is where I live.
D. This is where I live so I love this neighbourhood.
12.
A. The water looks warm but the wind makes it a bit too cool for swimming.
B. The water looks warm; but the wind makes it a bit too cool for swimming.
C. The water looks warm, but the wind makes it a bit too cool for swimming.
D. The water looks warm the wind makes it a bit too cool for swimming.
13.
A. This answer, I believe, is correct; or should I say, nearly correct.
B. This answer, I believe, is correct or should I say, nearly correct.
C. This answer, I believe, is correct, or should I say, nearly correct.
14.
A. Dipti's dog, Butch, is very lucky for Dipti nursed it back from near death.
B. Dipti's dog, Butch, is very lucky, for Dipti nursed it back from near death.
C. Dipti's dog, Butch, is very lucky; for Dipti nursed it back from near death.
15.
A. We found our car and quickly entered to get away from the cold.
B. We found our car; and quickly entered to get away from the cold.
C. We found our car, and quickly entered to get away from the cold.
Answers
1, C. 2, C. 3, B. 4, C. 5, D. 6, C. 7, A. 8, C. 9, D. 10, A. 11, B. 12, C. 13, A. 14, C. 15, A.