ACT English Restrictive vs. Nonrestrictive Clauses: Master Essential vs. Extra Information

Restrictive clause: Essential information that specifies which noun. No commas. Example: "The student who scored highest won the prize." (Which student? The one who scored highest. This is essential.) Nonrestrictive clause: Extra information about a noun that's already identified. Needs commas. Example: "Sarah, who scored highest, won the prize." (We know who Sarah is; the clause adds extra info.) Test: If removing the clause changes the sentence's core meaning, it's restrictive (no commas). If you can remove it without changing meaning, it's nonrestrictive (use commas). That introduces restrictive clauses. Which introduces nonrestrictive clauses (as discussed earlier). Which is comforted by commas.

Example pair: "The book that I read was good" (restrictive; which book? The one I read). "My favorite book, which I read last year, was good" (nonrestrictive; we know it's my favorite; the clause adds detail).

Mistake 1: Using commas around restrictive clauses. Restrictive clauses specify which noun and are essential; they don't get commas. Mistake 2: Forgetting to use commas around nonrestrictive clauses. Extra information about an already-identified noun needs commas on both sides. Mistake 3: Confusing the restriction of the clause with the restriction of the noun. Even a restrictive clause uses that, not which. The rule applies consistently. Always test: Is this clause essential (specifying) or extra (adding)? Commas depend on the answer.

During practice, identify the noun, ask if the clause is essential to specify it, and punctuate accordingly.

Sentence 1: "The dog that barks loudly is mine." Restrictive (which dog? The one that barks). No commas. Sentence 2: "My dog, which barks loudly, is a boxer." Nonrestrictive (we know it's my dog; barking is extra). Commas needed. Sentence 3: "The student who finished first received a prize." Restrictive (which student?). No commas. Sentence 4: "Mary, who finished first, received a prize." Nonrestrictive (we know Mary; finishing first is extra). Commas. Sentence 5: "I prefer restaurants that serve local food." Restrictive (which restaurants?). No commas. Contrast: "I prefer Antonio's, which serves local food" (nonrestrictive; we know which restaurant). Commas. Punctuate each correctly based on restrictiveness.

Find 10 restrictive-nonrestrictive questions from a practice test. For each, test whether the clause is essential. By the tenth question, restriction-based punctuation will be automatic.

Restrictive-nonrestrictive clause questions appear regularly on ACT English. Students who correctly distinguish restriction pick up 1 point because the comma rule follows logically from whether the clause is essential.

Drill the restriction test daily this week. On every practice test, mark clauses and test if they're essential before punctuating. By test day, you'll correctly punctuate restrictive and nonrestrictive clauses automatically.