3.1 Commas

3.1 Commas

The comma is arguably the most frequently used—and misused—punctuation mark in the English language. On the PERT Writing exam, you will encounter numerous questions testing your ability to identify correct comma placement. Commas serve to clarify meaning by separating words, phrases, and clauses. Understanding the specific rules that govern their use will significantly improve your sentence construction and exam performance.

1. Commas in Compound Sentences

A compound sentence contains two or more independent clauses (complete thoughts that can stand alone as sentences). When these independent clauses are joined by a coordinating conjunction (such as for, and, nor, but, or, yet, so—often remembered by the acronym FANBOYS), you must place a comma before the conjunction.

• Correct: The students studied diligently for the exam, and they all achieved passing scores.
• Incorrect: The students studied diligently for the exam and they all achieved passing scores. (Missing comma)
• Correct: We wanted to go to the beach, but it started raining heavily.

However, do not use a comma when the conjunction joins a compound predicate (two verbs sharing the same subject).

• Correct: The dog ran across the yard and leaped over the fence. (No comma before "and" because "leaped over the fence" is not an independent clause).

2. Commas after Introductory Elements

Introductory elements are words, phrases, or dependent clauses that precede the main independent clause of a sentence. A comma is required to separate these elements from the main clause, signaling a pause to the reader and clarifying where the core sentence begins.

Introductory Words: Single words like however, moreover, furthermore, yes, or well should be followed by a comma.

• Correct: Consequently, the committee decided to revise the proposal.
• Correct: Yes, you may turn in your assignment late.

Introductory Phrases: Prepositional phrases, participial phrases, and infinitive phrases acting as introductory elements require commas.

• Correct: After the long and exhausting meeting, everyone went home. (Prepositional phrase)
• Correct: Hoping to secure a front-row seat, she arrived at the theater an hour early. (Participial phrase)
• Correct: To fully understand the instructions, you must read the entire manual. (Infinitive phrase)

Introductory Dependent Clauses: When a dependent clause (starting with words like although, because, if, since, when) comes before an independent clause, it must be followed by a comma.

• Correct: Although the weather was terrible, they continued their hike.
• Note: If the dependent clause follows the independent clause, no comma is usually needed.
  • Correct: They continued their hike although the weather was terrible.

3. Items in a Series (The Oxford Comma)

When a sentence contains a list of three or more items (words, phrases, or clauses), commas are used to separate them. The comma placed immediately before the coordinating conjunction (usually and or or) is known as the serial comma or Oxford comma. For the purposes of standard academic writing and exams like the PERT, the Oxford comma is highly recommended to prevent ambiguity.

• Correct: The recipe requires flour, sugar, eggs, and milk.
• Without Oxford Comma (often considered less clear): The recipe requires flour, sugar, eggs and milk.

Consider how the Oxford comma resolves ambiguity:

• Ambiguous: I would like to thank my parents, Ayn Rand and God. (Are your parents Ayn Rand and God?)
• Clear: I would like to thank my parents, Ayn Rand, and God. (Three separate entities).

4. Commas with Nonessential (Parenthetical) Information

Commas are used to enclose nonessential or parenthetical information. These are words, phrases, or clauses that add extra details to a sentence but can be removed without changing the core meaning or grammatical structure of the sentence. If the information is nonessential, it should be set off with commas.

• Correct: My brother, who lives in New York, is coming to visit. (The clause "who lives in New York" is nonessential if I only have one brother).
• Correct: The new manager, an experienced executive, quickly implemented changes. (Appositive phrase acting as nonessential information).

Conversely, if the information is essential to identifying a noun or defining the meaning of the sentence, do not use commas.

• Correct: The students who failed the exam must attend tutoring. (The clause "who failed the exam" is essential because it specifies which students must attend tutoring).

5. Commas Between Coordinate Adjectives

When two or more adjectives independently modify the same noun, they are called coordinate adjectives and must be separated by commas. To determine if adjectives are coordinate, try two tests:

1. Can you insert the word "and" between them?
2. Can you reverse their order without changing the meaning? If yes to both, use a comma.

• Correct: It was a cold, dreary, exhausting day. (It was a cold and dreary and exhausting day. / It was a dreary, exhausting, cold day.)
• Incorrect: He wore a bright, blue shirt. (You wouldn't say "bright and blue shirt" or "blue bright shirt," because "bright" modifies the phrase "blue shirt." Thus, no comma is needed: He wore a bright blue shirt.)

Master the Nuances

The PERT Writing section will often present you with sentences where the comma placement subtly changes the meaning or where a comma is incorrectly inserted to interrupt the natural flow. Remember that commas represent pauses, but not every pause requires a comma. Rely on grammatical rules rather than simply reading the sentence aloud to listen for a breath. Practice identifying compound sentences versus compound predicates, and always check if a phrase is essential or nonessential to the sentence's fundamental meaning.