Answer:
Adverb of how refers to an adverb that qualifies the manner in which something is done.
Adverb of when refers to an adverb which tells when and how frequently an action is carried out.
Step-by-step explanation:
Adverb refers to a word or phrase which qualifies or modifies a verb, an adjective, etc.
Adverb of how
Adverb of how refers to an adverb that qualifies the manner in which something is done. An example of adverb of how is given as follows:
John is walking slowly.
In the example above, slowly is an adverb which qualifies the manner in which John is walking.
Adverb of when
Adverb of when refers to an adverb which tells when and how frequently an action is carried out. An example of adverb of when is given as follows:
David always reads in my room.
In the example above, always is an adverb which tells us how frequently David reads in his room.