She sings much better than I do. Identify the word class of the underlined word 'better'.

In the sentence 'She sings much better than I do', the word 'better' modifies the verb 'sings', telling us how she sings. Words that modify verbs are adverbs. 'Better' here is the comparative form of the adverb 'well'. It is not functioning as an adjective because it does not describe a noun. Hence the correct word class is Adverb.