Final answer:
The adverbs in the sentence are 'swiftly' and 'surely'.
Step-by-step explanation:
The adverbs in the sentence, 'Swiftly and surely, the owl swooped down on the mouse,' are 'swiftly' and 'surely.' Adverbs are words that modify verbs, adjectives, or other adverbs, providing more information about how an action is performed. In this sentence, 'swiftly' and 'surely' describe how the owl performed the action of swooping down on the mouse.
Learn more about Adverbs