Whenever a preposition starts what you think is a sentence, check for a subject, a verb, and a complete thought. If any one of those is missing, you have a fragment.
For a list of common prepositions, see “Subjects” in Chapter 15.
FRAGMENT | The plane crashed into the house. With a deafening roar. [With a deafening roar is a prepositional phrase that starts with the preposition with. The phrase has neither a subject nor a verb. It is a fragment.] |
Correct the fragment by connecting it to the sentence either before or after it. If you connect the fragment to the sentence after it, put a comma after the fragment to join it to the sentence.
FRAGMENT | The plane crashed into the house. From a height of eight hundred feet. |
CORRECTED | |
CORRECTED | From a height of eight hundred feet, the plane crashed into the house. |