What have we here? A torn sheet! (5)
I believe the answer is:
these
'what have we here? a' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'torn sheet' is the wordplay.
'torn' indicates anagramming the letters.
'sheet' with letters rearranged gives 'THESE'.
Can you help me to learn more?
(Other definitions for these that I've seen before include "He set (anag)" , "The persons or things here" , "Pronoun for people or things" , "Teh other ones from those" , "The items indicated here" .)