～てある
resultant state from intentional action
～てある is made by taking the て-form of a verb and adding ある. It is used with transitive verbs (verbs that take an object) and describes a state that remains because somebody did something on purpose.
In English it usually comes out as “has been done” (the door has been locked, a note has been left) with the feeling that a person deliberately arranged it that way.
1. A state left by a deliberate action
Use ～てある to describe how things are now as the result of someone’s intentional action. The thing affected is usually marked with が instead of を.
ドアに鍵がかけてある。
“The door is locked (someone locked it).”
- ドア = door
- に = location marker (on the door)
- 鍵（かぎ）= lock, key
- が = subject marker
- かけてある = has been locked (and is still locked)
Compare this with ～ている: ドアが閉まっている simply reports that the door is closed, while ～てある adds the idea that a person did it intentionally.
2. Something already done in preparation
～てある is also used to say that you have already done something to prepare for what is coming.
ホテルを予約してある。
“I have already booked a hotel.”
- ホテル = hotel
- を = object marker
- 予約してある（よやくしてある）= have booked (in advance)
How to form it
Transitive verb て-form + ある
- かける = to lock, to hang → かけてある = has been locked
- 書く（かく）= to write → 書いてある（かいてある）= is written
- 置く（おく）= to put → 置いてある（おいてある）= has been placed
Key idea
～てある describes a present state plus an invisible person behind it: someone did this on purpose, and the result is still here now.
Other N4 grammar
Updated .