Whereas adjectives are used to modify nouns, adverbs are used to modify verbs.
We can turn an い-adjective into an adverb by replacing the -い ending with -く.
| This bus is fast. | この バス は 早い。kono basu wa hayai. |
| Can (I) return home early today? | 今日 家 に 早く 帰れる か？kyou ie ni hayaku kaereru ka? |
We can turn な-adjectives into adverbs by replacing the -な ending with -に.
| Your girlfriend sings beautifully. | あなた の 彼女 は きれいに 歌う。anata no kanojo wa kireini utau. |
