Which of the following sections of dialogue is a sentence fragment? 1. They're gone!
2. Your hair!
3. What's crushing my legs?
4. This coat is so heavy!

“They’re gone!” & “Your hair!”

Both of those are sentence fragments because..

First, we don’t know what or who is “gone”. So that isn’t a complete sentence.

Second, we don’t know what is wrong with he/she/its “hair”. So that isn’t a complete sentence.

it is believed to be alfred, lord himself