Answer: "Five cars were pileup on the freeway" is a sentence fragment because the words "in" and "the" before "pileup" are missing.
Explanation: A sentence fragment is an incomplete sentence, that is to say a sentence that does not express a full idea. In general, a sentence fragment can be corrected by changing the punctuation marks or adding new words. "Five cars were pileup on the freeway" is a sentence fragment because it fails at communicating a complete idea. The words "in" and "the" must be added before the noun "pileup" in order to correct this fragment and make it a complete sentence
