Punctuation and Mechanics
Core concepts
Punctuation items cover commas (series, introductory elements, nonrestrictive phrases, before a coordinating conjunction joining two independent clauses), semicolons (between independent clauses and in complex lists), colons (after a complete clause introducing a list or explanation), apostrophes (possession and contractions), and capitalization (proper nouns, sentence openings, titles).
Common traps
- A comma splice: The road was icy, we drove slowly. Use a semicolon or a conjunction.
- A semicolon paired with a conjunction (; and) or placed before a dependent clause; both are wrong.
- A comma between subject and verb or before a restrictive clause that is essential to meaning.
- Apostrophe errors: it’s (it is) vs. its (possessive); singular student’s vs. plural students’.
- Over-capitalization: seasons, general academic subjects, and ordinary job titles stay lowercase; languages and specific names do not.
Rule of thumb
A semicolon needs a complete sentence on both sides. Test by replacing it with a period; if either side fails, choose another mark. Example: The experiment failed; the team revised its method. Both halves stand alone, so the semicolon is correct. For apostrophes, ask whether the word means “it is” (use it’s) or “belonging to it” (use its).