yoksiri neomu geonjohaeseo eojesbame gaseupgireul teureo nohasseoyo.

A natural breakdown is:

• 욕실이 = the bathroom
  • subject marker 이
• 너무 = too / so / very
• 건조해서 = because it was dry / being dry, so...
• 어젯밤에 = last night
• 가습기를 = humidifier
  • object marker 를
• 틀어 놓았어요 = turned on and left on

So the overall idea is:

• The bathroom was so dry, so I turned on the humidifier last night and left it on.

The last part, 틀어 놓았어요, is especially important because it does not just mean turned on; it suggests turned it on and left it that way.

이/가 marks the grammatical subject, while 은/는 marks the topic and often adds contrast or emphasis.

Here, 욕실이 너무 건조해서 simply presents the bathroom as the thing that was dry.

• 욕실이 너무 건조해서... = The bathroom was so dry, so...
• 욕실은 너무 건조해서... = As for the bathroom, it was so dry, so... or possibly the bathroom, unlike somewhere else, was so dry...

So 이 is the neutral, straightforward choice here.

건조해서 comes from 건조하다 = to be dry.

The ending -아/어서 connects clauses and often means:

• because
• so
• and therefore

So 건조해서 here means:

• because it was dry
• since it was dry
• it was so dry, so...

In this sentence, it gives the reason for the action in the second clause.

This is a very common question.

In Korean, when two clauses are connected, the first clause often does not need its own past tense marker if the time is already clear from context or from the final verb.

So:

• 욕실이 너무 건조해서 어젯밤에... 놓았어요 is completely natural.

Even though English says was dry, Korean often leaves the first clause in the non-past form and lets the overall past meaning come from:

• 어젯밤에 = last night
• 놓았어요 = past tense

건조했어서 is possible in some situations, but it usually sounds more marked, heavier, or less natural here.

Not always.

In textbook-style explanations, 너무 is often taught as too much / excessively, like English too.

But in real Korean, especially in speech, 너무 is also very commonly used to mean:

• very
• really
• so

So in this sentence, 너무 건조해서 can feel like:

• because it was too dry
• because it was so dry
• because it was really dry

All are reasonable depending on context.

Because 가습기 is the object of the verb.

The thing being turned on is the humidifier, so it takes the object marker:

• 가습기를

This is the normal pattern:

• 무엇을 틀다 = to turn on/run something

So:

• 가습기를 틀다 = to turn on the humidifier

Good question. Both verbs can relate to turning something on, but they are not used in exactly the same way.

켜다 is the general verb for turn on:

• 불을 켜다 = turn on the light
• 컴퓨터를 켜다 = turn on the computer

틀다 is often used for devices or systems that you set running, especially ones involving:

• air
• heat
• water
• sound/media

Examples:

• 에어컨을 틀다 = turn on the air conditioner
• 히터를 틀다 = turn on the heater
• 물을 틀다 = turn on the water
• 라디오를 틀다 = turn on the radio / put the radio on

For a humidifier, 가습기를 틀다 is very natural because it means to run the humidifier.

This is one of the most important points in the sentence.

틀었어요 simply means:

• turned it on

But 틀어 놓았어요 means:

• turned it on and left it on
• turned it on and left it that way

The grammar -아/어 놓다 often gives the idea of:

1. doing something in advance, or
2. doing something and leaving the result in place

Here it is the second meaning.

So the sentence suggests that the speaker did not just switch on the humidifier momentarily; they left it running.

It is past polite.

Here is the structure:

• 틀다 → 틀어
• 놓다 → 놓았어요 in the past
• together: 틀어 놓았어요

In this kind of construction, the tense usually appears on the second verb, the auxiliary-like 놓다.

So 틀어 놓았어요 means something like:

• turned it on and left it on
• had it turned on
• left it running

Yes. Very often in everyday speech, 놓았어요 becomes 놨어요.

So:

• 틀어 놓았어요 → 틀어 놨어요

Both are correct.

The longer form, 놓았어요, may sound a little more careful or written. The shorter form, 놨어요, is very common in normal conversation.

Yes, it can often be omitted.

에 is a time/location particle, and with many time expressions it marks when something happened.

So:

• 어젯밤에 = last night
• 어젯밤 = last night

Both are natural here.

The version with 에 can sound a little more explicitly time-marked, but there is no big difference in meaning.

In Korean grammar, 건조하다 is a descriptive verb often translated as an adjective in English.

So although English uses an adjective:

• dry

Korean uses a word that conjugates like a verb:

• 건조하다 = to be dry

That is why it changes form like this:

• 건조하다 = dictionary form
• 건조해요 = is dry
• 건조해서 = because it is dry / being dry

This is normal for Korean adjectives.

It is in the standard polite style, often called the -어요 style.

That means it is appropriate for:

• everyday conversation
• speaking politely to people you do not know well
• many normal situations

Comparable levels would be:

• 틀어 놓았어요 = polite
• 틀어 놨어 = casual/informal
• 틀어 놓았습니다 = more formal

So the sentence sounds natural, polite, and conversational.