Question

Fix the subject-predicate mismatches.
Though harder than all the others, Jeanne finished her puzzle before her friends finished theirs.

Answer 1

Well, the subject would be the puzzle and the predicate would be what describes the subject, "harder than all the others".

Answer 2

"Jeanne" is the subject of the verb "finished", and her "puzzle" is the direct object. The predicate includes the verb and all its modifiers, so the rest of the sentence (everything other than "Jeanne", the subject) makes up the predicate.

"Though harder than all the others" modifies "puzzle", not Jeanne, so it is a misplaced modifier and should be moved closer to "puzzle":

Jeanne finished her puzzle, though harder than all the others, before her friends finished theirs.