yatto ame ga yanda node, beranda ni hosite atta taoru wo naka ni ireta.

やっと means finally, at last, or after a long wait.

It often carries the feeling that something took longer than expected or that the speaker had been waiting for it to happen.

So in this sentence, やっと雨がやんだ suggests something like:

• The rain finally stopped
• At last, the rain stopped

It is more emotionally colored than a plain 雨がやんだ.

やむ is an intransitive verb meaning to stop when talking about things like:

• rain
• snow
• wind
• noise

So:

• 雨がやむ = the rain stops
• 雨がやんだ = the rain stopped

Because やむ is intransitive, the rain is treated as the thing that undergoes the change, not something that someone stops.

Because やむ is intransitive.

With intransitive verbs, the thing that changes state is usually marked by が. Here, rain is the thing that stopped, so:

• 雨がやんだ = the rain stopped

If you used を, that would suggest a transitive structure, but やむ does not work that way here.

Because the stopping of the rain happened before the next action.

The sentence is saying:

1. The rain finally stopped
2. So/Since that happened, I brought the towels inside

Using やんだので shows the reason or background for the later action.

So this is not just a generic because it stops raining idea. It is specifically:

• because it had stopped raining
• since the rain finally stopped

Both can mean because, but they have slightly different nuances.

• から often sounds more direct, personal, or assertive
• ので often sounds softer, more explanatory, and a little more neutral

So:

• 雨がやんだから、... = more direct: Because the rain stopped, ...
• 雨がやんだので、... = softer/explanatory: Since the rain stopped, ...

In a sentence like this, ので sounds very natural because the speaker is giving the reason for what they did.

This is a noun phrase where a whole clause modifies タオル.

Break it down like this:

• ベランダに = on the balcony
• 干してあった = had been hung out / was left hanging
• タオル = towel(s)

So:

ベランダに干してあったタオル = the towel(s) that had been hung out on the balcony

This is a very common Japanese pattern: a verb clause comes before a noun and describes it.

Examples of the same structure:

• 昨日買った本 = the book I bought yesterday
• 机の上に置いてあるかばん = the bag that is placed on the desk

This is a very good question, because the nuance matters.

干してあった comes from 干してある, which often describes a state resulting from someone’s intentional action.

So ベランダに干してあったタオル suggests:

• the towels had been intentionally hung out there
• they were in that state when the speaker is talking about them

This is slightly different from 干していた, which focuses more on the action/process of hanging or drying.

Compare:

• 干してあったタオル = towels that had been hung out and were there in that state
• 干していたタオル = towels that were being hung/dried, with a bit more focus on the activity or situation

In this sentence, 干してあった is natural because the speaker is referring to towels that had been put out and left there.

Here, に marks the place where the towels had been put/hung.

With 干す, Japanese often uses に for the place where something is hung or placed to dry:

• ベランダにタオルを干す = hang towels on the balcony
• 外に洗濯物を干す = hang laundry outside

So ベランダに干してあった means the towels had been hung on the balcony.

Literally, it means put (them) inside.

• 中 = inside
• に = into
• 入れた = put in / placed in

So タオルを中に入れた is literally I put the towels inside.

In natural English, that often becomes:

• I brought the towels inside
• I took the towels in

Japanese does not need a word like house or room here. 中 is enough because the destination is obvious from context.

Because Japanese often omits subjects when they are clear from context.

In this sentence, the person who brought the towels inside is not explicitly stated, but it is naturally understood to be the speaker or someone already known in the conversation.

So Japanese is not being vague in a strange way; it is just relying on context, which is very normal.

A natural English translation needs a subject, so we usually supply one:

• I brought the towels inside
• We brought the towels inside

depending on the situation.

It could be either towel or towels in Japanese, because Japanese nouns usually do not mark singular/plural the way English does.

So タオルを中に入れた could mean:

• brought the towel inside
• brought the towels inside

In real life, context tells you which one is meant. Since people often hang multiple towels on a balcony, English translations often use towels, but the Japanese itself does not force that.

A helpful way to parse it is:

• やっと雨がやんだので、
  since the rain finally stopped,
• ベランダに干してあったタオルを
  the towel(s) that had been hung on the balcony
• 中に入れた。
  (I) brought inside.

So the overall structure is:

[Reason/background] + [object] + [main action]

That is a very common Japanese sentence pattern.

Not in the same way.

In the original sentence:

• ベランダに belongs with 干してあった
• it describes where the towels had been hanging

Then:

• 中に入れた describes where the towels were moved to

So the sentence contrasts two locations:

• ベランダに = on the balcony
• 中に = inside

If you used から, that would mark a starting point, but that is not how the original phrase is built. The sentence is focusing on the towels that were on the balcony, then saying they were moved inside.

Yes, depending on context, that can sound very natural in English.

Japanese ので basically gives the reason/background, but in English, we sometimes express that more naturally as a time relationship:

• When the rain finally stopped, I brought the towels in.
• Once the rain finally stopped, I brought the towels in.
• Since the rain finally stopped, I brought the towels in.

All of these can fit, depending on the tone of the translation.

So even though ので is fundamentally a because/since connector, the best English translation may sometimes sound more like when or once.