Standard English Conventions: Boundaries & Sentence Structure
These questions test punctuation at sentence boundaries (commas, semicolons, periods, colons), subject-verb agreement, and correct pronoun/verb forms — mostly grammar, not comprehension.
Boundary punctuation cheat sheet
A period or semicolon can join two independent clauses (complete sentences); a comma alone cannot (that's a comma splice — a common wrong-answer trap). A comma CAN join an independent clause to a dependent clause, or join two independent clauses if paired with a conjunction (and, but, so...).
A colon introduces an explanation, list, or elaboration, and must follow a complete independent clause. Subject-verb agreement: the verb must match the true subject's number, not a noun in a prepositional phrase sitting next to the verb.
Worked Example
Choose the correct punctuation: 'The results were surprising ___ no one expected the treatment to work so quickly.'
- Both sides are independent clauses (each could stand alone as a full sentence).
- Two independent clauses need a period, semicolon, or comma+conjunction — a comma alone would be a splice.
Answer: A semicolon (or a period) correctly joins the two independent clauses.
Key terms (2)
- Comma splice
- Incorrectly joining two independent clauses with only a comma (no conjunction).
- Independent clause
- A group of words that could stand alone as a complete sentence.
Practice Quiz
Which choice completes the sentence with correct punctuation? "The committee reviewed every application carefully ___ several qualified candidates were ultimately turned away."