Adverbs are words that modify the word they are attached to. The word they are attached to can be, among others, a verb, an adjective, another adverb.
Adverbs of Manner
Adverbs of time are adverbs that add a descriptive value to a verb, or to how something is being done. To form an adverb of manner, we usually add the ending “-ly” to their adjective form.
For adjectives that end on -y, the “y” turns into an “I”, and we add “-ily”.
Examples: Happy – happily, crazy – crazily
For adjectives that end on -le, we remove the “e”, and ad “y”, instead of “ly”.
Examples: terribly – terribly (not terriblely), horrible – horribly (not horribley)
For adjectives that end on “ic”, we add “ally”.
Examples: terrific – terrifically, realistic – realistically
There are some adverbs that do not follow any of these rules. In some cases, adding “-ly” also changes the meaning of the word.