Recognizing fragments | Syntax | Khan Academy

Hello grammarians! David here along with my cousin Beth, who also happens to be a teacher. Say hello to the people, Beth.

"Hi, people!"

So today we are going to talk about sentence fragments. Beth, you cover these in classes that you teach. Could you tell me, please, what is a sentence fragment?

"Great! A sentence fragment is when a student writes a sentence and they think it's a sentence, but it's one that tells maybe what happens but doesn't include who. Or it might include who but doesn't tell what happens. So, sentence fragments don't tell the whole story. The way I would put it is that a fragment is a piece of a sentence that cannot stand on its own, but nevertheless incorrectly ends with a period."

So, "the whole story" for instance would be a fragment. "This is a fragment." It could be a sentence, but it's missing something. Beth, what is it missing? What is the whole story missing?

"Well, we've got a subject, but we don't have what we would call a predicate. In other words, so we're giving a subject, but we're not telling what happens to that subject."

All right, so "the whole story" began 10 years ago, and now we've got our subject here: the whole story. And now we've given it a predicate. Similarly, if we just had this predicate and we just said, "It began 10 years ago," well, that's not enough to be a sentence either. That's also a fragment because now we've got a predicate but no subject. Right? We're telling about something but we don't know what.

So, in order to be a sentence, you need to have both a subject and a predicate. You need to have a thing like a noun or a pronoun, and then you have to have something happen to that noun or pronoun or something performed by that noun or pronoun. Right? So, "the pancakes." Period. Is not a sentence, but "the pancakes were delicious" is. So you've got a part that names—that's your subject—and then you've got the part that finishes the thought—that's your predicate.

Let's look at another example. All right, what about "because of the snowstorm"? Is that a sentence, Beth?

"Nope!"

Why not?

"Well, you don't tell what happened because of that snowstorm. So, this is what we'd call not even a—I mean, it's not even a dependent clause. Right? This thing doesn't have, um, doesn't really have a subject or a verb. It's really just a prepositional phrase. So, 'because of the snowstorm,' something could happen, but we don't know what that is. So, 'because of the snowstorm, we stayed home from school.' So we've got this sentence here—this independent clause—right? 'We stayed home from school,' and that's a subject and a predicate. And if it were just 'stayed home from school.' Period. That wouldn't be a sentence. And if it were just 'we.' Period. That also wouldn't be a sentence. And if it were just 'because of the snowstorm.' Period. That wouldn't be a sentence. It doesn't have enough support to stand on its own. But altogether, 'because of the snowstorm, we stayed home from school.' Period. That is a sentence."

So, in order to make sure that you're building sentences, you have to make sure that what you've got is a subject and a predicate. You've got to have a subject and a verb. Put them together, slap on a period, you've got a sentence.

"You've got some good sentences there, David! You can learn anything."

"Dave it out and Beth out!"