In the sentence, "She quickly finished her homework," the underlined word "quickly" is an adverb. Here's why:
- An adverb is a part of speech that modifies verbs, adjectives, or other adverbs. It often answers questions such as how, when, where, or to what degree something is done.
- The word "quickly" describes how the action of finishing (verb) is performed. It tells us the manner in which she completed her homework.
- Therefore, "quickly" fits the definition of an adverb as it modifies the verb "finished" by indicating the speed of the action.
The correct part of speech for "quickly" in this context is: Adverb.