You do something now. You do it to get ready for later. It is like preparing for something.
Verb [て-form] + おくPrimary
You do something now. You do it to get ready for later. It is like preparing for something.
旅行の前に、ホテルの予約をしておこう。
Let's book the hotel before the trip (in preparation).
会議のために、資料をコピーしておきました。
I copied the materials in preparation for the meeting.
まだ使うから、パソコンは消しておかないでください。
I'm still using it, so please don't turn off the computer (i.e., please leave it on).
ケーキがまだ残っているから、冷蔵庫に入れておいて、後で食べよう。
There's still cake left, so let's put it in the fridge (and leave it there) and eat it later.
友達が来るから、部屋を掃除しとくね。
My friend is coming over, so I'll clean the room (in advance).
Sometimes, Japanese people shorten words. It's like saying "gonna" instead of "going to" in English. You will hear "〜とく" instead of "〜ておく". You will hear "〜どく" instead of "〜でおく". This helps you understand spoken Japanese better.
Both 〜ておく and 〜てある show something is ready. But they focus on different things. 〜ておく is about someone doing something to get ready. You use 'を' with the thing they prepare. 〜てある is about the thing being ready. It does not focus on who did it. You often use 'が' with the thing that is ready.
Use this when you want to say you will do something and leave it that way. You do not plan to change it back soon. For example, you open a window and leave it open.
More formal alternatives(1)
Less formal alternatives(1)
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