Adjective + する
Make Adjective
The adjective + する pattern is used when you (or another agent) actively change the state of something. It is the transitive counterpart to 〜なる (to become).
How It Works
To use this pattern, you must first convert the adjective into its adverbial form:
1. い-adjectives: Replace the final 〜い with 〜く.
Example: 早い（はやい） → 早くする（はやくする） "to make fast/hurry up."
⚠️ Irregular: The adjective 良い（いい） becomes よくする (not いくする).
2. な-adjectives: Replace the final 〜な with 〜に.
Example: 静かな（しずかな） → 静かにする（しずかにする） "to make quiet/be quiet."
3. Nouns: Add 〜に after the noun. This has two main meanings:
• Change: To make something into a certain state. Example: 半分（はんぶん） → 半分にする（はんぶんにする） "to cut in half."
• Decision: To decide on or choose something (e.g., from a menu). Example: コーヒーにする "I'll go with coffee."
Key Nuance:
This pattern requires an agent (someone doing the action) and usually takes the object marker を for the thing being changed. It implies that the change didn't just happen naturally; someone made it happen.
Examples (4)
- テレビの音を大きくしました。
I turned up the TV volume (made the sound louder).
Word by Word: TV's sound (object) big made.
Here, the い-adjective 大きい becomes 大きく to show the intentional action of increasing the volume.
- 部屋をきれいにしてください。
Please clean the room (make the room clean).
Word by Word: Room (object) clean-ly please do.
きれい is a な-adjective, so it takes に before する. This is a very common way to tell someone to tidy up.
- 塩を入れて、スープを熱くしました。
I put in salt and made the soup hot.
Word by Word: Salt putting-in, soup (object) hot made.
The speaker is the agent who changed the temperature of the soup.
- 次の休みは土曜日にしましょう。
Let's make the next day off Saturday (Let's decide on Saturday).
Word by Word: Next holiday (topic) Saturday to let's do.
When used with a noun + に, this pattern often carries the meaning of 'deciding on' or 'choosing' something.
Common Mistakes
Using the wrong particle for the object being changed.
部屋がきれいにしました。部屋をきれいにしました。Because する is a transitive action performed by an agent, you must use the object marker を for the thing you are changing. Using が would imply the room is doing the cleaning.
Using 〜に with い-adjectives.
安いにしてください。安くしてください。い-adjectives must use the 〜く form. The 〜に form is reserved for な-adjectives and nouns.
How It Connects
Learn This First
To understand 'adjective + する' (Make Adjective), you need to know how to manipulate both い-adjectives and な-adjectives into their adverbial forms. Specifically, い-adjectives change their final 〜い to 〜く, and な-adjectives use the particle に. These forms are then combined with the verb する to describe making something possess that quality.
- い-adjectives
Understanding how to identify and use い-adjectives is necessary because they must be conjugated to their adverbial form (ending in 〜く) before adding する.
Level 1 - な-adjectives
Understanding な-adjectives is necessary because they require the particle に to connect to the verb する.
Level 1 - Verb concepts
The pattern uses the verb する (to do) to express the action of causing a change in state, so basic knowledge of how verbs function is required.
Foundations
Related Patterns
- なるTo Become
〜なる describes a natural or spontaneous change in state ('to become'), whereas 〜する describes an intentional change caused by someone ('to make').
Level 1 - をObject Marker
The particle を is used to mark the object that is undergoing the change in state.
Level 1 - ことにするDecide to
This related pattern uses する to express a personal decision to perform an action, similar to how 'Noun + にする' expresses a choice.
Level 3
Words in This Pattern
Practice Adjective + する in Bubblegum
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