It’s important to remember: “When a sentence is incomplete.” Um, what? When a sentence is incomplete, no one knows what you’re talking about. A half-finished sentence makes for a half-baked thought.
- Whether the stolen shirt was in her purse.
- As if they hadn’t flirted already!
- No way he could eat any more.
Most incomplete sentences are linked to a sentence either before or after the incomplete phrase in question. Adding “The security guard wanted to see” to “whether the stolen shirt was in her purse” transforms an incomplete sentence about a stolen shirt into a perfectly understandable complete sentence.
Every complete sentence needs a subject — the person, place, thing, or idea that is doing or being something — and a predicate (which finishes an idea about the subject).