a) The “ku” form of the adjectives can be used as adverbs too:
私は あさ はやく おきます/ Watashi wa asa hayaku okimasu.
I wake up early in the morning.
私は よる おそく ねます/ Watashi wa yoru osoku nemasu.
I go to bed late in the night.
b) In the case of the verbal adjectives (ending in -na), in order to use them adverbially we have to replace the –na ending with –ni
私は げんき に あるく/ Watashi wa genki ni aruku.
I walk energetically.
• The verb なる/ Naru - to become, to get
a) Noun + Ni particle + Naru
わたし は おとな に なりました
Watashi wa otona ni narimashita
I became an adult.
b) Adjective in Ku + Naru
へや が きたなく なりました
Heya ga kitanaku narimashita
The room got dirty.
c) Adjective in Ni + Naru
まち が しずかに なりました
Machi ga shizuka ni narimashita
The city got quiet.