What is a sentence fragment?
In the simplest grammatical terms, a sentence fragment lacks a main—or independent—clause. Put more informally, a sentence fragment doesn't make a statement that can stand on its own.
How to identify and fix sentence fragments
Some understanding of grammar can help you to identify and fix sentence fragments. But a little intuition based on examples may be all you'll need to spot sentence fragments and fix them. There are two main types of fragments:
The first type doesn’t make a statement. It is all subject, no predicate—all actor, no action:
- The catalyst that initiated a chain reaction between the two test compounds in an acidic solution.
The verb initiated doesn’t save this sentence from being a sentence fragment. The subject is the entire sentence, beginning with the catalyst and ending with acidic solution. The sentence has no predicate.
Your strategy for converting the fragment into a full sentence depends on what you’re trying to say. You could, for example, make the initiation of a chain reaction your main point:
- The catalyst initiated a chain reaction between the two test compounds in an acidic solution.
Or you could develop the initial sentence by adding a predicate that tells us more about the catalyst:
- The catalyst that initiated a chain reaction between the two test compounds in an acidic solution had no effect on the same two compounds in a pH-neutral solution of water.
The second type of sentence fragment has a subject and a predicate, but the sentence still can’t stand on its own. Usually, that is because it begins with a word—a subordinating conjunction like although or because or when—that makes the sentence want to lean against a neighbouring one.
- Strategic voting played a key role in the Liberal victory. Although it would have made little difference in a system based on proportional representation.
The key to fixing the problem is often to join the two sentences:
- Strategic voting played a key role in the Liberal victory, although it would have made little difference in a system based on proportional representation.
Alternatively, you could replace the conjunction with a sentence adverb:
- Strategic voting played a key role in the Liberal victory. However, it would have made little difference in a system based on proportional representation.
Reading aloud is an excellent way to alert yourself to the presence of incomplete sentences.
When are sentence fragments appropriate?
Not all sentence fragments need to be fixed. Whether they do can depend on genre. In the hands of a skilled novelist, they may bring prose to life. The opening paragraph of Dickens's Bleak House consists mostly of fragments: "Michaelmas Term lately over, and the Lord Chancellor sitting in Lincoln's Inn Hall. Implacable November weather. As much mud in the streets as if the waters had but newly retired from the face of the earth . . ." Used judiciously, sentence fragments also have a place in journalism.
In more formal genres such as the academic essay, however, they should generally be avoided. To be sure, a sentence fragment can very occasionally supply an answer to a strategically placed rhetorical question: "What is the likely environmental consequence of more supply-side economic policy? Accelerated global warming." Or it can inject a refreshing note of informality into a closely argued paper: "The opposition party's objections had no effect on the sitting government. None at all." Experiment if you like, but do so sparingly!