Final answer:
The given sentence can be transformed using the key word 'admitted' to say 'David admitted to borrowing your favorite jumper.'
Step-by-step explanation:
This question is related to the subject of English as it involves a sentence that can be transformed using the key word 'admitted'.
The given sentence is: 'I borrowed your favorite jumper,' David said. To transform this sentence using 'admitted,' we can say: 'David admitted to borrowing your favorite jumper.'
The grade level for this question is High School as it involves understanding sentence structure and vocabulary.