Deciding whether to use a comma or a semicolon can be very stressful. You can reduce the stress by learning how to punctuate compound sentences and series.
Look at these sentences:
Colbart hates grammar.
He often skips grammar class.
Both are independent clauses. They’re called independent clauses because they can stand on their own as sentences. Note that a clause has to have at least one subject and one verb. In the first sentence, the subject is Colbart, and the verb is hates. In the second sentence, the subject is he, and the verb is skips.
One independent clause is a simple sentence. Two simple sentences can be joined by a coordinating conjunction (for, and, nor, but, or, yet, so—FANBOYS is a handy acronym) to make one compound sentence. A comma comes before the coordinating conjunction:
Colbart hates grammar, and he often skips grammar class.
Take out the subject “he” in second clause, and the comma before “and” comes out too. The compound sentence becomes a simple sentence with one subject (Colbart) and two verbs (hates and skips).
Colbart hates grammar and often skips grammar class.
Two independent clauses can (almost) NEVER be joined by a just a comma This is an error called a comma splice.
X Colbart hates grammar, he often skips grammar class.
(Very short, pithy clauses can be joined by a comma: Man plans, God laughs.)
BUT two independent clauses CAN be joined by a semicolon to form a compound sentence:
Colbart hates grammar; he often skips grammar class.
Two clauses joined by a semicolon must be closely related thoughts that belong together.
X Colbart hates grammar; his sister is very tall.
Three or more items in a series are separated by commas:
Attending the meeting were Bob Windbag, Sara Soporific, and Dan Gobbledygook.
BUT if the series itself contains commas, the items are separated by semicolons:
Attending the meeting were Bob Windbag, Administration; Sara Soporific, Human Resources; and Dan Gobbledygook, Mission Statement Facilitation.
Transitional words and phrases (sometimes called conjunctive adverbs) such as accordingly, consequently, curiously, furthermore, for example, however, moreover can join two independent clauses: When one of these words or phrases joins two independent clauses, a semicolon comes before it and a comma after it:
Colbart hates grammar; consequently, he often skips grammar class.
When one of these transitional words or phrases interrupts the flow of a single clause, it is set off by commas:
Colbart, however, loves math.
Punctuate the following sentences with commas or semicolons as appropriate and decide whether each sentence is a simple sentence (one clause) or a compound sentence (two clauses):
- Bart and his friends often drink too much and get sick.
- Priscilla gets very involved in chess problems sometimes she forgets to eat.
- Don had no coffee beans in his flamed Sambuca and Linda had four in hers.
- Doug and Evie took the coffee beans out of their flamed Sambuca and offered them to Don.
- We just met Sam Joe’s father Marion Sam’s second wife and Cleo and Eleanor their two Siamese cats.
- Ursula and Theo love taking long walks together however Theo is getting old and can’t walk very far anymore.
- Martin will try to get out of running for a third term but the board won’t let him.
- Geraldine never worries about being late she is however rarely late for dinner.
- Cedric loves dogs but has never owned one.
- Cedric loves dogs however he has never owned one.
Answers: 1. No commas or semicolons (simple) 2. Priscilla gets very involved in chess problems; sometimes she forgets to eat. (compound) 3. Don had no coffee beans in his flamed Sambuca, and Linda had four in hers. (compound) 4. No commas or semicolons (simple) 5. We just met Sam, Joe’s father; Marion, Sam’s second wife; and Cleo and Eleanor, their two Siamese cats. (simple) 6. Ursula and Theo love taking long walks together; however, Theo is getting old and can’t walk very far anymore. (compound) 7. Martin will try to get out of running for a third term, but the board won’t let him. (compound) 8. Geraldine never worries about being late; she is, however, rarely late for dinner. (compound) 9. No commas or semicolons (simple) 10. Cedric loves dogs; however, he has never owned one. (compound).