bame deowoseo seonpunggireul teureo nohgo jasseoyo.

밤에 means at night or during the night.

The particle 에 is often used with time expressions to mean at / in / on.
So:

• 밤 = night
• 밤에 = at night

In this sentence, it sets the time background: at night, it was hot...

This comes from the adjective 덥다 meaning to be hot.

덥다 is a ㅂ-irregular adjective, so when it is followed by a vowel-starting ending like -어서, the ㅂ changes to 우:

• 덥다
  • -어서
• → 더워서

So 더워서 means because it was hot or since it was hot.

Here, -아서 / -어서 gives a reason or cause, similar to:

• because
• so
• since

So 더워서 means:

• because it was hot
• it was hot, so...

In this sentence, it connects the reason to the action that follows:

• 밤에 더워서 = Because it was hot at night...

선풍기 means electric fan.

So:

• 선풍기 = fan
• 선풍기를 = the fan + object marker

This is the thing being turned on.

를 is the object particle. It marks 선풍기 as the direct object of the verb.

In other words, it shows that the speaker did something to the fan.

Here, the verb is 틀다, so:

• 선풍기를 틀다 = to turn on the fan

Great question. 틀다 has several meanings depending on context.

With appliances or devices like:

• 선풍기 = fan
• 에어컨 = air conditioner
• 라디오 = radio
• 텔레비전/TV = TV

틀다 often means to turn on or to run them.

So:

• 선풍기를 틀다 = turn on the fan
• 에어컨을 틀다 = turn on the air conditioner

You may also hear 켜다 for turn on, especially with lights or electronics. But with things like fans, air conditioners, radios, and TVs, 틀다 is very common.

틀어 놓고 comes from 틀어 놓다.

The grammar -아/어 놓다 means something like:

• do something and leave it that way
• do something in advance and keep that state

So:

• 틀고 잤어요 = I turned it on and slept
• 틀어 놓고 잤어요 = I left it on and slept

That second version is more natural here because the important idea is not just that the speaker turned on the fan, but that the fan remained on while they slept.

In this pattern, 놓다 does not mean the literal put/place meaning.

Instead, in -아/어 놓다, it adds the sense of:

• doing something beforehand
• leaving the result in place
• maintaining the state

So 틀어 놓다 means:

• turn it on and leave it on
• have it running

That is why the whole sentence sounds like:
It was hot at night, so I slept with the fan on.

-고 connects verbs, usually like and, then, or while depending on context.

Here it links two actions:

1. 선풍기를 틀어 놓고 = having left the fan on
2. 잤어요 = slept

So the meaning is roughly:

• I left the fan on and slept
• I slept with the fan left on

It is not just a simple list of actions; together with -아/어 놓다, it gives the sense that the fan stayed on during the sleep.

잤어요 is the polite past form of 자다 (to sleep).

• 자다 = to sleep
• 잤어요 = slept

The speaker is talking about a completed event in the past: they slept with the fan on.

Even though 더워서 does not have an explicit past marker, the whole sentence is understood in the past because the final verb is in the past.

Korean often leaves out the subject when it is obvious from context.

So even though there is no explicit 저는 or 제가, the sentence is naturally understood as something like:

• I slept with the fan on because it was hot at night.

This is very normal in Korean. If the speaker wanted to emphasize the subject, they could say:

• 저는 밤에 더워서 선풍기를 틀어 놓고 잤어요.

But usually it is not necessary.

Yes, that is a fairly literal translation.

But the more natural English translation is usually:

• It was hot at night, so I slept with the fan on.

That is because 틀어 놓고 implies that the fan was left running, not just turned on once as a separate action.

So the literal meaning and the natural meaning are close, but the natural English version better captures the nuance.

In this sentence, 더워서 clearly means because it was hot.

The ending -아서 / -어서 often marks cause or reason when followed by another clause. So here, the heat is the reason for sleeping with the fan on.

In other contexts, it can sometimes feel softer, like since or so, but the basic idea is still a causal connection.

Both are possible, and both mean roughly I slept with the fan on.

The difference is mostly in verb choice:

• 켜다 = turn on
• 틀다 = turn on/run certain devices, especially things like fans, air conditioners, TVs, radios

For a fan, 틀다 sounds very natural.
So:

• 선풍기를 틀어 놓고 잤어요 = very natural
• 선풍기를 켜 놓고 잤어요 = also understandable and possible

In everyday Korean, many speakers especially prefer 틀다 with 선풍기.