Introduction
The comma is one of the most frequently used punctuation marks in English. Using commas correctly helps clarify meaning and ensures your writing flows smoothly. This lesson covers the basic uses of commas that every writer should know.
Basic Uses of Commas
1. Separating Items in a Series
Use commas to separate three or more words, phrases, or clauses in a series.
Examples:
- I need to buy milk, bread, eggs, and cheese. (words)
- She enjoys swimming, hiking, and playing tennis. (gerund phrases)
- He washed the car, mowed the lawn, and fixed the leaky faucet. (clauses)
Note: The final comma before the conjunction (and, or, nor) is called the Oxford or serial comma. While some style guides make it optional, using it consistently helps avoid ambiguity.
2. Separating Coordinate Adjectives
Use commas to separate two or more adjectives that independently modify the same noun.
Examples:
- It was a long, tiring day.
- The old, dusty, leather-bound book sat on the shelf.
Test: If you can insert "and" between the adjectives or reverse their order without changing the meaning, they are coordinate adjectives and require commas.
3. Setting Off Introductory Elements
Use a comma after introductory words, phrases, or clauses.
Examples:
- Yes, I will attend the meeting.
- In the morning, we'll discuss the project.
- After the movie ended, we went for dinner.
4. Separating Independent Clauses
Use a comma before a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so) that joins two independent clauses.
Examples:
- The sun was setting, and the temperature was dropping.
- She wanted to go to the concert, but she couldn't afford the tickets.
5. Setting Off Nonessential Elements
Use commas to set off information that is not essential to the basic meaning of the sentence.
Examples:
- My brother, who lives in Boston, is visiting next week.
- The movie, which won three Academy Awards, is now available for streaming.
6. Setting Off Direct Address
Use commas to set off the name of a person being directly addressed.
Examples:
- Thank you, John, for your help.
- Lisa, could you pass the salt?
7. Setting Off Quotations
Use commas to set off direct quotations from the rest of the sentence.
Examples:
- "I'll be there soon," she promised.
- The teacher said, "Please open your books to page 42."
8. In Dates, Addresses, and Numbers
Use commas in specific parts of dates, addresses, and large numbers.
Examples:
- July 4, 1776, was an important date in American history.
- She lives at 123 Main Street, Boston, Massachusetts, 02108.
- The population of the city is 1,234,567.
Common Comma Errors to Avoid
1. Comma Splice
Don't use a comma alone to join two independent clauses.
Incorrect:
The movie was excellent, the actors were talented.
Correct options:
The movie was excellent, and the actors were talented.
The movie was excellent; the actors were talented.
2. Missing Comma with Coordinating Conjunction
Don't omit the comma before a coordinating conjunction that joins two independent clauses.
Incorrect:
The sun was setting and the temperature was dropping.
Correct:
The sun was setting, and the temperature was dropping.
3. Unnecessary Comma Between Subject and Verb
Don't place a comma between the subject and verb of a sentence.
Incorrect:
The tall, handsome actor, was cast in the lead role.
Correct:
The tall, handsome actor was cast in the lead role.
Summary
Commas serve many important functions in writing, from separating items in a list to setting off nonessential information. Using commas correctly helps ensure your writing is clear, precise, and professional.
Practice
Identify where commas should be placed in the following sentences:
- After the storm passed the sky cleared and a rainbow appeared.
- My sister who is a doctor works at the local hospital.
- Please bring your notebook pencil eraser and textbook to class.
- Yes we will be attending the conference next week.
- The old wooden bridge collapsed during the heavy rainfall.
Quiz: Commas - Basic Uses
Test your understanding of comma usage with this short quiz.
Question 1
Which of the following sentences correctly uses commas to separate items in a series?
- A) I need to buy milk bread eggs and cheese.
- B) I need to buy milk, bread, eggs and cheese.
- C) I need to buy milk, bread, eggs, and cheese.
- D) I need to buy milk, bread eggs, and cheese.
Question 2
In which sentence are commas correctly used with coordinate adjectives?
- A) The small, wooden, table needs to be repaired.
- B) She wore a beautiful blue, silk dress.
- C) He drove a new, expensive, German car.
- D) We stayed in a charming old, Victorian house.
Question 3
Which sentence correctly uses a comma after an introductory element?
- A) In the morning we'll discuss the project.
- B) After the concert ended the audience applauded.
- C) Yes I will attend the meeting.
- D) Before leaving for work, she checked her email.
Question 4
Which sentence correctly uses a comma to join independent clauses?
- A) The sun was setting and the temperature was dropping.
- B) The sun was setting, the temperature was dropping.
- C) The sun was setting, and the temperature was dropping.
- D) The sun was setting and, the temperature was dropping.
Question 5
Which of the following is a comma splice error?
- A) The movie was excellent, and the actors were talented.
- B) The movie was excellent; the actors were talented.
- C) The movie was excellent, the actors were talented.
- D) The movie was excellent. The actors were talented.