Let's define...
Everyone worked hard on the projects for the science fair. What part of speech is hard in this sentence?
c. HARD is an adverb
Linda took a long drink of water. What is the word long in this sentence?
D. LONG is an adjective
Jess skates better than Tony. What part of speech is better in this sentence?
BETTER is an adverb
Only one person arrived late for the party. What part of speech is late?
LATE is an adverb
Which word could not be an adverb: soon, well, probably, tomorrow, costly
costly
The long white envelope looked quite ordinary. What part of speech is quite?
QUITE is an adverb