If the adjective ends with 'ic', we add '-ally'.

basic - basically

BUT

public - publicly

If the adjective ends with 'le', we replace the 'e' at the end with 'y'

possible - possibly

horrible - horribly

​If the adjective ends in with 'y', we replace the 'y' with an 'i' and add '-ly'

easy - easily

merry - merrily

Adverbs of manner -Formation

​ Adverbs of manner - Formation

Some adjectives do not change form at all.

fast - fast

straight - straight

hard - hard

high - high

late - late

wrong - wrong