goes on a ます-stem and means you did something and then left it that way, when you should have put it back: a door left open, a light left on. It is casual and carries a note of blame. With
it says what someone did, and with
it describes the state.
。
Please don't leave the air conditioner on.
。
The door's been left open.
。
It's a waste to leave the water running.
The stem is the one in front of ます: gives , gives .
っぱなし or まま
after a た-form also means "left as it is", but it's neutral. っぱなし adds that the situation is careless or annoying.
。
I slept with the window open.
。
I went to sleep and left the window wide open.
Doing something nonstop
With a verb of continuing action – standing, sitting, walking, talking – っぱなし means you kept doing it the whole time without a break. Usually that is tiring, though not always: is laughing the whole time.
。
I've been on my feet since this morning and I'm exhausted.
さん3。
I walked for three hours without a break.
Lingaku