Here's why:
* Abstract nouns represent concepts, ideas, qualities, or states that cannot be physically touched. Examples include: happiness, freedom, love, justice.
* Adverbs modify verbs, adjectives, or other adverbs, providing information about how, when, where, or to what extent something happens.
In the sentence "I hardly finished my work," "hardly" tells us to what extent the speaker finished their work. It modifies the verb "finished."
Let me know if you'd like more examples of abstract nouns or adverbs!