Key SAT and ACT Grammar and Punctuation Rules:

---

1. Periods & Semicolons

• Semicolon = Period: Used between two complete sentences.
  • Correct: “London is an old city. It has been inhabited for 2,000 years.”
  • Correct: “London is an old city; it has many new buildings.”
• Before Conjunctive Adverbs: Like “however,” “therefore.”
  • Correct: “London is an old city; however, it has many new buildings.”
• Watch for Sentence Boundaries: Avoid “sentence boundary” errors by reading each sentence fully.
  • Incorrect: “Barbara McClintock… genes, she won the award.”
  • Correct: “Barbara McClintock… genes. She won the award.”

2. Colons & Dashes

• Colons & Dashes Introduce Lists/Explanations:
  • Before a list: “Visitors… attractions: museums, castles, shops.”
  • Before an explanation: “The Wall lost its purpose: enemies came from the sea.”
• Colons and dashes can introduce full sentences or fragments. Must follow a complete thought.

3. Comma + FANBOYS (For, And, Nor, But, Or, Yet, So)

• Comma + FANBOYS = Period = Semicolon:
  • Correct: “London is old, but some parts are modern.”
• Comma Splices: Avoid joining two sentences with a comma.
  • Incorrect: “London is old, it has modern parts.”
  • Correct: “London is old. It has modern parts.”
• Comma + FANBOYS + Verb = WRONG:
  • Incorrect: “London is old, but has many buildings.”
  • Correct: “London is old but has many buildings.”

4. Commas & Dependent Clauses

• Dependent Clauses: Cannot stand alone.
  • Incorrect: “Because London is old it has buildings…”
  • Correct: “Because London is old, it has buildings…”

5. Transitional Words & Phrases

• Types:
  • Continues: “in addition,” “moreover.”
  • Cause and Effect: “therefore,” “thus.”
  • Contradictory: “however,” “nevertheless.”
• Cross out the transition to find the sentence’s relationship.

6. Non-Essential Information

• Punctuation Options: Use two commas, two dashes, or two parentheses.
  • Incorrect: “London, which is old has modern parts.”
  • Correct: “London, which is old, has modern parts.”

7. Commas with Names & Titles

• Determine Essential vs. Non-Essential:
  • No commas if essential.
  • Two commas if non-essential.

8. Additional Comma Uses & Misuses

• Use commas: To separate items in a list, after introductory phrases, or between adjectives.
• Do not use commas: Before/after prepositions, between subjects and verbs, or before/after “that.”

9. Apostrophes (Plural vs. Possessive)

• Nouns:
  • Singular: add ‘s (e.g., the cell’s DNA).
  • Plural: add s’ (e.g., the cells’ DNA).
• Pronouns:
  • It’s = It is; Its = possessive form.

10. Pronouns & Nouns

• Agreement: Singular nouns = singular pronouns, plural nouns = plural pronouns.
  • Incorrect: “Frida Kahlo… It was influenced…”
  • Correct: “Frida Kahlo… They were influenced…”

11. Subject-Verb Agreement

• Singular vs. Plural:
  • Incorrect: “The Monarch and the Red Admiral is…”
  • Correct: “The Monarch and the Red Admiral are…”

12. Verb Tense

• Consistency: Keep verb tenses consistent.
  • Incorrect: “Frida Kahlo earned renown… She is influenced…”
  • Correct: “Frida Kahlo earned renown… She was influenced…”

13. Parallel Structure & Word Pairs

• Lists:
  • Incorrect: “Pamela Meyer has collaborated… and analyzing.”
  • Correct: “Pamela Meyer has collaborated… and analyzed.”

14. Dangling Modifiers

• Correct Placement:
  • Incorrect: “Born in 1907, self-portraits were…”
  • Correct: “Born in 1907, Frida Kahlo was…”

15. Faulty Comparisons

• Equivalent Items:
  • Incorrect: “The work of… well-known as Frank Lloyd Wright.”
  • Correct: “The work of… as that of Frank Lloyd Wright.”

16. Question Marks

• Direct vs. Indirect Questions:
  • Direct: “How much do babies understand?”
  • Indirect: “How much babies understand.”

17. Shorter is Better (ACT & Paper-Based SAT)

• When in doubt, choose the shortest grammatically correct option.

18. Adjectives vs. Adverbs (ACT Only)

• Adjectives modify nouns; adverbs modify verbs.

19. Pronoun Case (ACT Only)

• Correct: “My mother and I attended…”

20. Diction & Idioms

• Use correct prepositions and verbs.
  • Correct: “Effective at keeping…”
  • Incorrect: “Effective with keeping…”

---

Master these rules to boost your SAT and ACT scores!