Most sentence fragments are phrases, or subordinate clauses, or combinations of the two. Don't let the length of the sentence be your guide. A sentence can be two words ( He jumps) and a sentence fragment can be fifty words.
Recognizing fragments
At first glance, a sentence fragment may look like a sentence because it begins with a capital letter and ends with a period. When you look more closely, you'll see that the group of words is missing one or more of the elements required to make it a sentence: a subject, a verb, and a grammatically complete thought.
Because the mayor wanted more coverage than a single newspaper story. (fragment)
This example is a subordinate clause. It is missing an independent clause that would complete the thought.
Because the mayor wanted more coverage than a single newspaper story, we called a press conference for all media.
When you write a sentence beginning with a subordinating conjunction, make sure that an independent clause follows the subordinate clause.
We saw the boys standing there. Laughing and throwing cans all over the front lawn. (fragment)
A sentence here is followed by a fragment, a participial phrase that cannot stand alone. The problem could be solved if the period after there were changed to a comma.
He pointed at Tanya. The woman who wore the hard hat and the tool belt. (fragment)
The pronoun who makes this a relative clause that can't stand alone. Collectively, all of the words in italics act as an appositive identifying Tanya, and the appositive should be joined to the main clause with a comma.
The chair of the committee, whose term was dependent on his party's being in power, which was, according to the polls, unlikely to be the case after the next election. (fragment)
This example is more complicated, but it's still a fragment, consisting of a subject and two subordinate clauses, each containing phrases. You don't need to identify all the elements in this fragment, but you should realize that a predicate for the subject of the sentence ( chair) is missing. To make it a complete sentence, add a predicate; for example: The chair of the committee, whose term was dependent on his party's being in power, which was, according to the polls, unlikely to be the case after the next election, insisted on bringing the motion to a vote.
The last example is typical of the sophisticated fragments that might escape your notice. Keep your eye on the three key requirements: subject, verb, and complete thought. It's particularly important to check a complicated sentence to make sure it isn't a complicated fragment.
Acceptable fragments
A few sentence fragments are acceptable, although a teacher may prefer that you always avoid them. Experienced writers may use fragments for specific reasons.
In dialogue, fragments are appropriately conversational.
“Where are you going?” I asked.
“Out for a walk.” She glowered at me.
In other situations, fragments can create a desired effect, make a point emphatically, or answer a question they've asked:
Many of the people who drove by refused to stop and help. But not all of them.
Scorsese had offered me a bit part in the movie. The chance of a lifetime! My girlfriend wanted me to turn it down.
Why should you consider a two‐year rather than a four‐year college? For many reasons.
Before you consider using an intentional fragment, be sure you understand correct sentence structure, because an unintentional fragment is a glaring error. Also, be sure using a fragment is warranted. Could you achieve the same effect without it? In the second example above, a dash after movie would achieve the same effect that the fragment does.
Scorsese had offered me a bit part in the movie— the chance of a lifetime!