Sentence or Phrase

They will be, as soon as you add periods.

Anonymous"They are" and "He is" ,is this a sentence ?

They are fragments.

They would work only in answer to a question.

Who is coming to the party?

Who is picking up Grandma at the airport?

Who asked to have some tea?

Stated all on their own, they are meaningless.

Question: "Are these fragments?"

Incorrect answer: "They are."

Question: "Are these sentences"?

Correct answer: "They are."

"Is he sorry?"

"He is."

As Barbara said," Stated all on their own, they are meaningless." Without context, to me, they are fragments. With context added, they are used in conversation.

He is. He is what. No sense to me.

Is he clever?
He is. (Now it makes sense. Context, context, context)

Anonymous"They are" and "He is" ,is this a sentence ?

Okay. How would you classify the line from the Neil Diamond song, "I am," I said ? And was what he said a sentence?
Is it a meaningless sentence, or a meaningless phrase or a meaningless sentence fragment?[:^)]

I don't think you can use every word used by a singer as a yardstick in discussing English.

Without context, to me, "I am" is meaningless.

For sure!

What's the difference between a meaningless sentence and a meaningless sentence fragment?

I'm more concerned with fragments, not meaningless sentence.

To me, "I am" without context is not a meaningless sentence. It is a fragment.

1. I did.

2. a. Who knocked?
b. I did.

How do I explain to the original poster that 2. b. is a sentence, but 1. is not?