To be complete, a sentence needs a subject and a predicate. You can think of them as the protagonist and the drama1 or as the topic and its state of being. The subject is (or includes) a noun and the predicate is (or includes) a verb. Even very short sentences always have both.
- Gregor awoke.
- The sky is green.
- I do.
- It was.
These sentences may be uninformative, but they are complete. In fact, even one word can be a complete sentence.
In commands like these (called the imperative mood in grammar circles), the subject you goes without saying.
Of course, an exclamation (or interjection) is considered a complete sentence even when it doesn’t follow the subject-predicate format.
But interjections are a part of speech unto themselves.
|In the rec room, the chanting to summon the demon was coming to a close.|
A fragment is a sentence that’s missing either a subject or a predicate. Just as a very short sentence can still be complete, a long sentence can still be a fragment.
- The blind, white grubs inside the silk-lined bassinet, tucked under a yellow woollen blanket. X
This tells us all about the subject, grubs, but doesn’t tell us what they’re doing.
- The blind, white grubs lay inside the silk-lined bassinet, tucked under a yellow woollen blanket. ✓
- The blind, white grubs inside the silk-lined bassinet were tucked under a yellow woollen blanket. ✓
- Heaving and pulsing in their sleep, their tiny legs whispering restlessly. X
Here we have a wealth of verbs, but we don’t know who or what is undertaking the action.
- They heaved and pulsed in their sleep, their tiny legs whispering restlessly. ✓
- In the rec room, the chanting to summon the demon coming to a close. X
Don’t be confused by the verb coming; it’s not a predicate. As part of the participial phrase “coming to a close,” it’s acting as an adjective, describing the subject, not driving the sentence.
- In the rec room, the chanting to summon the demon was coming to a close. ✓
- In the rec room, the chanting to summon the demon came to a close. ✓
The presence of both a subject and a predicate doesn’t guarantee your sentence is complete. A clause can have its own subject and predicate, even though it’s part of a larger sentence.
- We finished that bottle of chianti when the cats came over for dinner.
The clause “when the cats came over for dinner” has both a subject and a predicate, but by itself it’s still a fragment.
- When the cats came over for dinner. X
- The cats came over for dinner. ✓
The word when sets up expectations the sentence doesn’t fulfill, leaving the reader hanging. When is a subordinating conjunction, which makes this a dependent clause; a dependent clause, as its name suggests, can’t stand on its own. To put it another way, clauses that begin with words like although, because, if, since, that, until, unless, and while will always be fragments by themselves.
- When the cats came over for dinner, we opened a bottle of wine. ✓
|When the cats came over for dinner, we opened a bottle of wine.|
When Is It Okay to Use Sentence Fragments?
Although sentence fragments are a big no-no in English class, you probably see them all the time—in fiction, in advertising, in blogs. (Possibly even in this blog.) You wouldn’t want incomplete sentences in your cover letter or college essay, but in the right context they can add punch to your prose. For example, an author might use them to heighten tension during a dramatic scene, or you might use them for humour or as part of a casual, friendly style. And they can make dialogue sound more realistic, as few of us talk in complete sentences all the time.
- Suki scanned the inky waves. There! Rising from the depths. A tentacle.
- Would I babysit the larvae? Not for a million bucks.
- Worst. Blog. Ever.
- “I feel weird,” said Gregor. “Kind of buggy.”
As is often the case, you can get away with breaking the rules provided you understand them. A sentence fragment can be either a sign of sloppiness or an effective writing tool. How will you know which it is? Context.
1. Constance Hale, Sin and Syntax
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