ACT English: Apostrophe Rules That Eliminate Half Your Errors

Rule 1: Singular possessives add 's. Example: "The student's notebook." Rule 2: Plural possessives (ending in s) add only an apostrophe. Example: "The students' notebooks." Rule 3: Irregular plural possessives add 's. Example: "The children's toys" (children is plural but does not end in s). Rule 4: Contractions replace missing letters with an apostrophe. Example: "It is" becomes "It's" (apostrophe replaces "i"). These four rules cover 95% of apostrophe errors on ACT English; memorize and apply them mechanically.

Common confusion: "The dog wagged its tail" versus "It's a beautiful day." In the first, "its" is a possessive pronoun with no apostrophe (like "his" or "her"). In the second, "it's" = "it is," so it needs an apostrophe. This distinction alone catches 40% of apostrophe errors.

Trap 1: Confusing "its" (possessive) with "it's" (contraction). Trap 2: Adding an apostrophe to regular plurals. "The cats ran" not "The cat's ran." Trap 3: Forgetting the 's on singular possessives. "The boss's decision" not "The boss' decision." (Modern usage adds 's even after s.) Trap 4: Confusing possessives with contractions in context. "The school's fundraiser" (possessive) versus "The school is closed" (never "school's is"). Trap 5: Not recognizing irregular plurals. "People's votes," "men's room," not "peoples'" or "mens'." Identify which trap you fall into by reviewing your practice test errors; focus your drill there.

Self-check: Read every apostrophe on a practice test and ask yourself: "Is this a contraction or a possessive?" If contraction, underline the original two words it replaces. If possessive, underline the owner and confirm you used 's or ' correctly.

Sentence 1: "The girls' backpacks were left at home." Sentence 2: "Its important to check the answer before submitting." Sentence 3: "All the boss's concerns were noted." Sentence 4: "The team won it's biggest game yesterday." Sentence 5: "The childrens' toys were scattered everywhere." For each, identify if the apostrophe is correct or incorrect. If incorrect, fix it. Check your work by asking: "Is this a contraction or a possessive?" Do this drill twice, correcting any errors until you understand why.

Answers: 1) Correct. 2) Incorrect; "Its" should be "It's" (it is important). 3) Correct. 4) Incorrect; "it's" should be "its" (possessive, not contraction). 5) Incorrect; "childrens'" should be "children's" (irregular plural, add 's).

Apostrophe errors account for 2-3 questions per ACT English section and are entirely mechanical. You do not need judgment; you just need to remember four rules. Spending 20 minutes to memorize and drill these rules will earn you 2 free points because apostrophe questions have no gray area.

Write the four rules on a card and carry it with you this week. Every time you see an apostrophe in daily reading, pause and apply the rules. By test day, apostrophe errors will be extinct from your writing.