Common errors with commas and coordinating conjunctions

Estimated reading time: 4 minutes

One of the most common challenges English learners face is the proper use of commas with coordinating conjunctions. Coordinating conjunctions, like and, but, or, nor, for, so, and yet, help connect ideas in writing. However, improper punctuation with these words can lead to confusion and grammatical errors.

In today’s NRTC English, I have outlined some of the most frequent mistakes and how to avoid them, explained in simple terms with relatable examples.

1. Comma Splice

Error: Using a comma between two independent clauses without a coordinating conjunction.
Example:

• Incorrect: I went to the market, I bought some apples.
• Correct: I went to the market, and I bought some apples.

Fix: Use a coordinating conjunction after the comma, or replace the comma with a semicolon if no conjunction is used.

2. Missing Comma Before Coordinating Conjunction in a Compound Sentence

Error: Omitting the comma before a coordinating conjunction that joins two independent clauses.
Example:

• Incorrect: She loves painting and she enjoys photography.
• Correct: She loves painting, and she enjoys photography.

Fix: Insert a comma before the coordinating conjunction when connecting two independent clauses.

3. Unnecessary Comma Before Coordinating Conjunction

Error: Placing a comma before a coordinating conjunction that does not connect two independent clauses.

Example:

• Incorrect: He likes tea, and coffee.
• Correct: He likes tea and coffee.

Fix: Remove the comma if the coordinating conjunction connects two parts of a sentence that are not independent clauses.

ALSO READ

• “Every day” vs. “everyday”: How to use them correctly
• Mastering subordinate clauses for proper use of commas in English
• Differences between cause and course, coarse and coerce
• How to use “its” and “it’s” correctly
• Is it correct to say “chalks”?

4. Comma Between Items in a Compound Predicate

Error: Using a comma between verbs or verb phrases that share the same subject.

Example:

• Incorrect: She sings, and dances beautifully.
• Correct: She sings and dances beautifully.

Fix: Avoid placing a comma between two verb phrases that share the same subject unless it’s part of a list with more than two items.

5. Comma Before Coordinating Conjunction in a List

Error: Misunderstanding the use of the Oxford comma in lists.
Example:

• Incorrect (if you prefer Oxford comma): I bought apples, oranges and bananas.
• Correct (with Oxford comma): I bought apples, oranges, and bananas.

Fix: Decide whether to use the Oxford comma (before the final and or or in a list). Be consistent throughout your writing.

6. Forgetting the Comma When Using So as a Coordinating Conjunction

Error: Omitting a comma before so when it connects two independent clauses.
Example:

• Incorrect: It was raining hard so we stayed inside.
• Correct: It was raining hard, so we stayed inside.

Fix: Place a comma before so if it introduces an independent clause.

7. Confusing Coordinating Conjunctions with Conjunctive Adverbs

Error: Using a comma with words like however, therefore, or meanwhile, which are not coordinating conjunctions.
Example:

• Incorrect: She was late, however, she managed to catch the train.
• Correct: She was late; however, she managed to catch the train.

Fix: Use a semicolon or a period instead of a comma before conjunctive adverbs.

Practice Tips

1. Identify independent clauses: Test if both parts of the sentence can stand alone. If they can, use a comma and a coordinating conjunction.
2. Beware of lists: Check if a comma is necessary before the final and or or.
3. Edit for clarity: Read the sentence aloud; if the pause feels unnatural, the comma might be unnecessary.

These strategies will help avoid most errors with commas and coordinating conjunctions.