～く・～に (adverbs)
Use adjective forms to describe how or when an action happens
You'll be able to change い-adjectives and な-adjectives into forms that modify verbs.
父は丁寧に車を洗っています。
chichi wa teinei ni kuruma o aratte imasu.
What do you think this sentence means?
My father is carefully washing the car.
Describe how an action happens
An adjective can describe the manner of an action. Here, 丁寧に tells us that father is washing the car carefully. The verb still tells us what he does.
Use ～く for い-adjectives and ～に for な-adjectives. The English translation may use an adverb such as “carefully,” or a phrase such as “in large letters.”
い-adjectives
い → く
早い → 早く
hayai → hayaku
early → early (modifying an action)
な-adjectives
stem + に
静か → 静かに
shizuka → shizuka ni
quiet → quietly
Exception
いい → よく
いい → よく
ii → yoku
good → well; carefully
Change the final い to く
Remove only the final い of an い-adjective and add く before the action: 早い → 早く. The verb carries tense and politeness; the adverb does not change for a past action.
いい is irregular: its adverb is よく. In よく聞いてください, よく means “carefully” or “well.” In other contexts it can mean “often,” so read it together with the action.
蓮は早く起きます。
ren wa hayaku okimasu.
Ren gets up early.
名前を大きく書いてください。
namae o ookiku kaite kudasai.
Please write your name in large letters.
よく聞いてください。
yoku kiite kudasai.
Please listen carefully.
Use に after a な-adjective
Use the な-adjective stem plus に, without な or だ. 静かな → 静かに. Remember that きれい is a な-adjective even though it ends in い: use きれいに.
芽衣は静かに本を読んでいます。
mei wa shizuka ni hon o yonde imasu.
Mei is reading a book quietly.
芽衣は字をきれいに書きます。
mei wa ji o kirei ni kakimasu.
Mei writes neatly.
父は丁寧に説明します。
chichi wa teinei ni setsumei shimasu.
My father explains carefully.
朝は道が混むから、早く家を出ます。
asa wa michi ga komu kara, hayaku ie o demasu.
The roads get crowded in the morning, so I leave home early.
薬の説明を丁寧に読んでください。
kusuri no setsumei o teinei ni yonde kudasai.
Please read the medicine instructions carefully.
図書館だから、静かに話してね。
toshokan da kara, shizuka ni hanashite ne.
We're in the library, so talk quietly, okay?
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