Sentence structure — fragments and run-ons
Conventions of Standard English
It usually sounds like
- “Which of the following is a complete sentence?”
- “Which sentence contains a fragment?”
- “What is the best way to correct the underlined portion?”
- “Which revision best combines the two sentences?”
The trap
The longest option looks the most complete. Length has nothing to do with it — a sixteen-word group with no main verb is still a fragment, and two correct sentences joined by a comma is still an error.
What to do
- Find the subject and the main verb of each option before you read it for meaning.
- If a word like because, although, when, or which starts the group, it is dependent and needs a main clause.
- If two complete sentences are joined, check what joins them: a period, a semicolon, or a comma plus one of for, and, nor, but, or, yet, so.
- Watch for -ing words posing as verbs. Running, having, being are never main verbs on their own.
Two worked examples
Which is a complete sentence? (A) The supervisor, who had worked there eleven years and knew every customer. (B) The supervisor knew every customer.
Thinking — A has a subject, supervisor, but the relative clause who had worked… absorbs both verbs. Nothing states what the supervisor did. B has subject (supervisor) and main verb (knew).
Answer — B. A is a fragment despite being more than twice as long.
Correct the underlined portion: The order arrived late, we had to reschedule the install.
Thinking — Cover the comma. Both halves stand alone as sentences, so a comma alone cannot join them — this is a comma splice. Adding so names the relationship the sentence already implies.
Answer — The order arrived late, so we had to reschedule the install. Deleting the comma instead would make it worse, not better.