N598/98
〜く・〜に＋動詞（副詞化）
い-adjective (stem) + く + Verbな-adjective + に + Verb
Meanings
adverbial use of adjectives: い-adjective stem + く / な-adjective + に, modifying a verb
About this pattern
Explanation
Adjectives modify verbs by changing form: い-adjectives replace い with く (早い → 早く起きます = wake up early); な-adjectives take に (静か → 静かに話します = speak quietly).