Reading & WritingStandard English ConventionsHigh frequency

SAT Reading & Writing: Commas with Nonessential (Parenthetical) Clauses

37+ practice questions in Praczo

What you need to know

The concept, explained

  • 1

    A nonessential (parenthetical) clause adds extra information that can be removed without changing the core meaning. It must be set off by commas on both sides.

  • 2

    An essential clause cannot be removed — it identifies who or what is being discussed. No commas.

  • 3

    Test: remove the clause. If the sentence still makes clear sense AND identifies the right person/thing, the clause is nonessential → use commas.

  • 4

    "Which" typically introduces nonessential clauses (use commas); "that" typically introduces essential clauses (no commas).

  • 5

    A person's name, when used as an appositive, is usually nonessential: "My brother, Jake, called last night."

Common mistakes
  • Omitting the closing comma after a nonessential clause — both the opening and closing commas are required.
  • Using "which" without a comma or "that" with a comma, reversing the essential/nonessential distinction.
Try a sample question

SAT-style practice

Which sentence correctly uses commas with a nonessential clause?

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