Adverbs can modify other adverbs to indicate the degree or manner of the action described by the adverb.
Examples:
i. Extremely
- She runs extremely fast.
- He speaks extremely softly.
- They arrived extremely early.
ii. Rather
- It's rather cold outside.
- She's rather quiet today.
- He's rather annoyed.
iii. Surprisingly
- She dances surprisingly gracefully.
- He speaks surprisingly fluently.
- They arrived surprisingly early.
iv. Rewritten Sentence:
- She runs in an extremely fast manner.