Mastering Apostrophes: Possessives, Contractions, and Common Mistakes on the SAT

Apostrophes serve two functions on the SAT: marking possession (John's book, the girls' team) and forming contractions (it's, can't, don't). The most common error is confusing its (possessive pronoun) with it's (contraction for "it is"). Another common error is using apostrophes for plurals (the 1990s, not the 1990's). Understanding when apostrophes are used and when they are not prevents most apostrophe errors.

Possession requires an apostrophe before the s for singular nouns (cat's toy) and after the s for plural nouns (cats' toys), except for irregular plurals which take apostrophe-s (children's toys). Contractions always use apostrophes (can't, don't). Plurals never use apostrophes unless the plural is a letter or number mentioned as a noun (three A's, two 4's).

The most common apostrophe errors on the SAT are its/it's confusion and incorrect plural apostrophes. When you see an apostrophe in a passage, pause and verify: Is this possession (needs apostrophe for singular, no apostrophe for possessive pronouns like its, theirs, yours) or a contraction (needs apostrophe) or a plural (no apostrophe)? One-second verification catches most errors.

Practice identifying apostrophe errors in 20-30 sample sentences. Mark every apostrophe and verify it is correct. Build the habit of questioning apostrophes until verification becomes automatic. After working through 30-40 examples, your brain will flag apostrophe errors instinctively.

Its is possessive (like his or her). It's always means "it is." Substitute "it is" when you see it's; if the sentence still makes sense, the apostrophe is correct. "It's a beautiful day" = "It is a beautiful day" (correct). "The team lost it's momentum" does not mean "The team lost it is momentum" so the apostrophe is wrong (should be "its momentum").

Use this substitution test on every its/it's in your practice passages. After doing this 20-30 times, your brain will use the test automatically and you will catch errors instantly.

Each week, take a 100-word passage and mark every apostrophe. Verify each one: Is it correctly placed for possession or contraction? Is a plural incorrectly using an apostrophe? After correcting five passages (one weekly for five weeks), apostrophe errors become obvious to you and errors on test day will jump out.

Maintain apostrophe accuracy by checking your own writing during every practice. When you write possessives or contractions, verify apostrophe placement. This habit prevents errors from creeping back in and keeps skills sharp until test day.