ACT English: The Complete Comma Rules Cheat Sheet

Rule 1: Introductory phrases need a comma. "After the storm, the sky was clear." Rule 2: Independent clauses joined by a conjunction need a comma. "She studied hard, and she passed the test." Rule 3: Non-restrictive clauses (extra information) need commas. "My brother, who lives in Tokyo, visits every year." Rule 4: Items in a series need commas. "Red, green, and blue are primary colors." Rule 5: Direct addresses, transitions, and interrupters need commas. "Well, I think you're right." or "Sarah, can you help?" These five rules are mechanical; apply them to identify which choice is correct before you consider other grammar.

Examples: "Because it was raining we stayed home" is missing a comma after "raining" (Rule 1). "He wanted to go but she preferred to stay" is missing a comma before "but" (Rule 2, requires comma before coordinating conjunction). "My neighbor who lives next door is a teacher" is missing commas around "who lives next door" if it is non-restrictive (extra info), so it should be "My neighbor, who lives next door, is a teacher" (Rule 3).

Mistake 1: Adding commas where they do not belong. "The book is red, and expensive." No comma before "expensive" unless it is part of a series or compound sentence. Mistake 2: Misidentifying restrictive vs. non-restrictive clauses. "Students who study regularly succeed" needs no commas (who is restrictive). "My students, who are hardworking, succeed" needs commas (who is non-restrictive). Mistake 3: Comma splices (already covered in an earlier article). Mistake 4: Omitting the serial comma. Modern ACT accepts both "red, green and blue" and "red, green, and blue," but the serial comma is safer. When in doubt about whether a clause is restrictive, ask: "Does removing this clause change the core meaning?" If yes, restrictive (no commas). If no, non-restrictive (commas needed).

Test: "The book which was on the table is red." Is "which was on the table" restrictive? Remove it: "The book is red." The meaning is essentially the same, so the clause is non-restrictive and needs commas: "The book, which was on the table, is red."

Sentence 1: "After the presentation everyone applauded loudly." Sentence 2: "The car is fast, and reliable." Sentence 3: "My daughter who is a doctor, helps at the clinic." Sentence 4: "Players need endurance strength and speed." Sentence 5: "Well I think you should apply for the job." For each, (1) identify which rule applies, (2) determine if a comma is missing or extra, (3) correct the sentence. Do this drill daily for one week; comma intuition develops faster with repetition than almost any other skill.

Corrections: 1) Add comma: "After the presentation, everyone applauded." (Rule 1). 2) Remove comma: "The car is fast and reliable." (No comma needed in compound adjectives without "and"). 3) Remove commas: "My daughter who is a doctor helps at the clinic." (Restrictive; if you remove it, meaning changes). 4) Add commas: "Players need endurance, strength, and speed." (Rule 4, series). 5) Add comma: "Well, I think you should apply." (Rule 5, interjection).

Comma errors account for 4-6 questions per ACT English section. Mastering the five rules lets you answer these mechanically in seconds. One afternoon spent drilling comma rules will earn you 3-4 points on test day, more points per hour than any other skill on ACT English.

Start today: Write the five rules on a card and keep it in your pocket. Read it every morning for one week. By test day, comma placement will be automatic, and you will never miss a comma question again.