SAT That vs. Which: Choosing the Correct Relative Pronoun for Restrictive Clauses

A restrictive (essential) clause limits the meaning of the noun it modifies and is necessary to identify which noun is meant. A non-restrictive (non-essential) clause adds extra information that could be removed without changing the core meaning. In standard American English, "that" introduces restrictive clauses and takes no comma, while "which" introduces non-restrictive clauses and requires a comma before it.

Example: "The report that was submitted late was rejected" (restrictive, no comma, only the late report was rejected). Versus: "The annual report, which covers four quarters, was submitted on time" (non-restrictive, comma required, the "which" clause just adds information). A reliable test: read the sentence without the clause and ask whether the sentence still identifies the same specific noun; if not, the clause is restrictive and "that" is correct.

SAT writing questions may present a sentence using "which" where "that" is needed, or vice versa. The fastest diagnostic is the comma check: if the clause is set off by a comma, "which" is correct; if no comma is present, "that" is correct for restrictive clauses. However, the SAT sometimes omits the comma even when "which" is used, so the comma alone is not always enough. You must also test whether the clause is essential to the sentence's meaning.

Common traps: (1) using "which" without a comma, creating ambiguity; (2) using "that" for people instead of "who." People take "who" (restrictive) or "who" with a comma (non-restrictive), not "that" or "which." If the antecedent is a person, replace "that" or "which" with "who" and check whether commas are needed based on whether the clause is essential.

Micro-example 1: "The book that I borrowed was overdue." Restrictive (identifies which book), correct use of "that," no comma. Micro-example 2: "The library, which opens at nine, is on Main Street." Non-restrictive (adds extra information), correct use of "which," comma required. Micro-example 3: "Students which scored above 1400 received merit awards." Incorrect because the antecedent is people; correct form: "Students who scored above 1400 received merit awards" (restrictive, no comma).

A simple if-then decision: If the clause identifies the specific noun from a group and the sentence would be ambiguous without it, use "that" (no comma). If the clause adds optional description, use "which" (with comma). If the antecedent refers to people, bypass that/which entirely and always use "who" with the appropriate punctuation for restrictive vs. non-restrictive.

Write three sentences per day for seven days: one with a restrictive "that" clause, one with a non-restrictive "which" clause, and one with a "who" clause. After writing, underline the clause, confirm the comma status, and test the removability rule. This produces 21 practice sentences that build an instinct for the distinction far faster than memorizing abstract rules. Review your error log for any misclassifications.

To self-check: (1) find the relative clause; (2) try removing it; (3) if meaning changes significantly, use "that" (no comma); (4) if the sentence still makes sense and nothing is left unclear, use "which" (with comma). The seven-day sentence-writing drill is more effective than recognition-only practice because production forces you to commit to a choice rather than recognize it passively.