Lesson article
Spot the signal, compare it, then read it in context
Read all 3 sections in order. Notice the target form, compare it with the nearby alternative, then use the reading and practice below to check the meaning in context.
Section 1 of 3
Decide on your own action
ことにする means that someone decides to do something. The decision usually belongs to the person in the sentence, not to a rule or outside organization.
Target signal
毎朝日本語を読むことにしました。
I decided to read Japanese every morning.
読むことにしました reports a decision that has been made.
Vocabulary notes
- しました
- did
- ことに
- into the situation that; in the arrangement that
- 日本語
- Japanese language
Compare in context
今日から電車で学校へ行くことにします。
Starting today, I’ve decided to go to school by train.
ことにします can announce a decision being made now.
Vocabulary notes
- ことに
- into the situation that; in the arrangement that
- します
- do
- から
- from; because
Compare in context
今週は甘い物を食べないことにします。
This week, I’ve decided not to eat sweet things.
A negative plain form before ことにする means deciding not to do it.
Vocabulary notes
- ことに
- into the situation that; in the arrangement that
- します
- do
- こと
- thing; matter; fact
Section 2 of 3
Deciding not to do something
Negative decisions are common with habits, safety, health, and time management. Look for a plain negative verb before ことにする.
Target signal
夜はスマホを使わないことにした。
I decided not to use my smartphone at night.
使わないことにした shows a deliberate habit change.
Vocabulary notes
- ことに
- into the situation that; in the arrangement that
- スマホ
- smartphone
- こと
- thing; matter; fact
Preview
雨の日は自転車に乗らないことにしました。
I decided not to ride my bicycle on rainy days.
The decision is tied to a condition: rainy days.
Vocabulary notes
- しました
- did
- ことに
- into the situation that; in the arrangement that
- 自転車
- bicycle
Preview
忙しいので、今日は出かけないことにします。
Because I am busy, I’ve decided not to go out today.
The reason comes first, then the decision.
Vocabulary notes
- ことに
- into the situation that; in the arrangement that
- します
- do
- 忙しい
- busy
Section 3 of 3
Narrative choices after thinking
In stories and essays, ことにする often appears after hesitation, advice, or comparison. It marks the moment when the person chooses one path.
Target signal
迷ったが、応募することにした。
I hesitated, but decided to apply.
The が contrast leads into the final decision.
Vocabulary notes
- 応募する
- to apply; to enter an application
- ことに
- into the situation that; in the arrangement that
- こと
- thing; matter; fact
Preview
友だちと相談して、旅行を来月にすることにしました。
After discussing it with a friend, we decided to make the trip next month.
にする plus ことにする shows choosing an option.
Vocabulary notes
- しました
- did
- にする
- to choose; to decide on
- ことに
- into the situation that; in the arrangement that
Preview
お金をためるために、アルバイトを増やすことにした。
I decided to increase my part-time work in order to save money.
The purpose explains why the decision was made.
Vocabulary notes
- アルバイト
- part-time job
- ために
- in order to; for the purpose of
- ことに
- into the situation that; in the arrangement that