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The Boundaries Playbook: six marks, one decision

Roughly one in every eight Reading & Writing questions is decided by a single mark. Learn the six marks by what each one requires, then take the 6-question quiz — passage on the left, choices on the right, exactly like the real test.

Take notes as you go. Write down each mark and the one thing it requires — students who copy the rules by hand before the quiz score noticeably higher on boundaries questions. Keep your notes next to you and use them on the 6 questions below.

Part 1 — the lesson

.

Period

Sentence + Sentence. Two complete thoughts, fully separated.

  • 🔑 Test: cover the mark. Is there a full sentence on BOTH sides? If yes, a period is always legal.
  • ⚖️ A full sentence = subject + verb + a complete thought (it can stand alone).
  • 🚫 Trap: the SAT gives you a period option where the right side is a fragment ("Being the first…"). Fragment = eliminate.
  • ✅ If a period works, a semicolon works too — so the SAT will never make both correct at once.

Correct

The kiosks spread quickly. Cashier headcount barely changed.

Wrong

The kiosks spread quickly. Because managers reassigned staff.

Step 1 / 6

Part 2 — walk the decision tree

The 3-second decision tree

1

Cover the blank. Is there a COMPLETE sentence on the left?

🔑 Complete = subject + verb + stands alone.

Part 3 — rapid fire warm-up

Rapid fire — legal or illegal?

0 / 8🔥 0 streak

The trail was flooded, we turned back.

Part 4 — your cheat sheet

Copy this into your notes

  • .

    Period

    Sentence + Sentence. Two complete thoughts, fully separated.

  • ;

    Semicolon

    Sentence ; Sentence. Same job as a period, softer break.

  • :

    Colon

    Sentence : list, example, quote, or explanation.

  • ,

    Comma

    Joins a PHRASE to a sentence, or sets off extra info — never two sentences alone.

  • —

    Dash

    A loud comma. One dash = colon-ish; two dashes = a pair of commas.

  • ∅

    Nothing at all

    Sometimes the correct answer is zero punctuation.

Part 5 — the quiz · keep your notes open

;

Ready for the quiz?

6 boundaries questions, one at a time. Hints on every question, full explanation the moment you answer. Notes out — no rush.

That was one lesson out of dozens.

The full course runs this format across every domain — animated lessons, thousands of real questions, hints on all of them, and targeted practice on your weak spots.

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