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JLPT N4Verb Forms

くする / にする— Make something become (a quality)

Used to intentionally make something take on a quality. An い-adjective becomes adverbial (drop い, add く) + する; a な-adjective/noun takes に + する = 'make [something] [quality].'

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Pro lessonUNIT 31 · VERB FORMS

Structure · 形

[い-adj: drop い + く] + する | [な-adj / noun + に] + する

Examples · 例文

  • 音楽を大きくしてください。

    Ongaku wo ookiku shite kudasai.

    Please turn up the music (make it louder).

    大きい → 大きく + する = make big/loud

  • 部屋をきれいにします。

    Heya wo kirei ni shimasu.

    I will clean/tidy up the room.

    きれい (na-adj) + に + する = make clean

  • 問題を簡単にしてほしい。

    Mondai wo kantan ni shite hoshii.

    I want you to make the problem easier.

    簡単 (na-adj) + に + する = make simple/easy

Usage notes · 注意

  • い-adj: 大きくする (make big), 高くする (raise the price), 短くする (shorten).
  • な-adj: きれいにする (make clean), 静かにする (make quiet), 簡単にする (simplify).
  • Compare 〜くなる (become, by itself — intransitive) vs 〜くする (deliberately make — transitive).

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones くする is tested against.

vsくなる / になる

なる = something changes on its own ('becomes'); する = someone deliberately changes it ('makes it'). 大きくなる (it grew) vs 大きくする (I enlarged it).

vsな-adj + にする

い-adjectives use くする; な-adjectives and nouns use にする — matching each adjective's adverbial connector.

More verb forms

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