hyudaeponeul kyeon chaero jamdeureosseoyo.

I fell asleep with my phone still on.

Breakdown of hyudaeponeul kyeon chaero jamdeureosseoyo.

• ~을: object particle
• 휴대폰: cell phone
• 잠들다: to fall asleep
• 켜다: to turn on

Questions & Answers about hyudaeponeul kyeon chaero jamdeureosseoyo.

What does 켠 mean here, and what dictionary form does it come from?

켠 comes from the verb 켜다, which means to turn on.

In this sentence, 켠 is the adnominal (modifier) form of 켜다, used before 채로. So:

• 켜다 → to turn on
• 켠 → turned on / in the state of having turned on

This form is a little irregular-looking because 켜다 does not become 켜은. It contracts to 켠.

So 휴대폰을 켠 채로 means something like:

• with the phone left on
• while the phone was still on

What does 채로 mean?

채로 means in the state of, while remaining, or without changing that state.

It is used when something stays as it is, and another action happens during that unchanged state.

So in 휴대폰을 켠 채로 잠들었어요, the idea is:

• the phone was turned on
• that state continued
• then the person fell asleep

A useful way to think about -ㄴ/은 채로 is:

• leave something as it is and do something else

More examples:

• 문을 연 채로 나갔어요.
  He left with the door open.

• 불을 켠 채로 잤어요.
  I slept with the light on.