Respuesta :
Adverbs refer to the words which modify an adjective, a verb or an adverb. Adverbs further answers to the following question of,
How? Where? When? and Why?
Therefore, in the sentence, yesterday Rachel worked slowly because she was so tired.
Words which function as an adverb are- yesterday, so and slowly.
Yesterday answers from the following questions of when?
So acts as a modifier to an adverb slowly, and
Slowly modifies an adjective slow.
