asa hayaku sitakusite, hiru made ni ie ni modoru tumori da.

Because 早く is the adverb form of the い-adjective 早い.

• 早い = early
• 早く = early / quickly, used to modify a verb

Here it modifies 支度して, so the idea is get ready early.

Compare:

• 早い朝 = an early morning
• 朝早く支度する = to get ready early in the morning

Yes, in a natural way. 朝早く means early in the morning.

You can think of it as:

• 朝 = morning
• 早く = early

Together, they form a time expression. Japanese often places time expressions before the verb without needing extra words.

So:

• 朝早く支度して = getting ready early in the morning

A native English speaker might expect something more like in the morning, but Japanese often just places the time noun directly in the sentence.

Time words in Japanese often appear without a particle, especially when they are functioning as general time expressions.

So 朝早く is perfectly natural.

You could sometimes see particles with time words in other contexts, but here 朝 without a particle is the most natural choice.

For example:

• 明日行く = I’ll go tomorrow
• 朝起きる = wake up in the morning

Adding a particle after 朝 here would sound less natural or change the nuance.

支度して is the て-form of 支度する, which means to get ready, to prepare, or to make preparations.

So:

• 支度する = to get ready
• 支度して = getting ready / get ready and...

In this sentence, the て-form connects this action to the next one:

• 支度して、昼までに家に戻る
  = get ready, and return home by noon

Yes, usually. The て-form often connects actions in sequence.

So this sentence strongly suggests:

1. get ready early in the morning
2. then return home by noon

The て-form does not always mean strict step-by-step order in every sentence, but here that is the most natural interpretation.

This is a very common question.

• まで = until
• までに = by / before

In this sentence, 昼までに means by noon or before noon.

That means noon is a deadline.

Compare:

• 昼まで家にいる = stay at home until noon
• 昼までに家に戻る = return home by noon

So までに is the right choice because the sentence is about completing the action before a certain time.

The particle に marks the destination of movement.

So:

• 家に戻る = return to home

With movement verbs like 行く, 来る, 戻る, and 帰る, に often shows where someone is going.

You can think of it as similar to to in English.

Yes, 家へ戻る is possible.

Both に and へ can mark direction/destination with movement verbs, but there is a slight difference:

• に emphasizes the destination itself
• へ emphasizes direction toward it

In many everyday sentences like this one, に is the more common and natural choice.

Both can relate to returning, but they are not identical.

• 帰る often means go home or return to one’s base
• 戻る means return back to a previous place or state

So 家に戻る is natural if the speaker is focusing on going back to the house.

A learner may expect 家に帰る, and that would also be natural in many situations. The choice depends on nuance:

• 帰る sounds more like go home
• 戻る sounds more like return back

つもりだ expresses intention or plan.

So:

• 戻るつもりだ = I intend to return / I plan to return

This is not just a plain future statement. It specifically shows what the speaker has in mind or plans to do.

Compare:

• 昼までに家に戻る。 = I’ll return home by noon.
• 昼までに家に戻るつもりだ。 = I intend to return home by noon.

The second one highlights the speaker’s intention.

Not exactly. It means the speaker intends or plans to do it, but it does not guarantee that it will happen.

So it is stronger than a vague possibility, but weaker than an absolute promise.

It is about the speaker’s current intention.

Most likely, yes.

Japanese often omits subjects when they are understood from context. With つもりだ, the subject is very often the speaker, so the natural reading is:

• I intend to get ready early in the morning and return home by noon.

But in the right context, another subject could be understood.

だ is the plain-style copula here, attached to つもり.

• つもりだ = plain style
• つもりです = polite style

So the sentence is in a casual/plain register.

A polite version would be:

• 朝早く支度して、昼までに家に戻るつもりです。

Not exactly. In everyday Japanese, 昼 often means noon or midday, depending on context.

So here 昼までに is best understood as:

• by noon
• before midday

A learner might first think 昼 only means daytime, but in many common expressions it refers more specifically to the middle of the day.

In isolation, yes, 早く can mean either early or quickly depending on context.

But here, because it appears with 朝:

• 朝早く = early in the morning

So early is the correct interpretation here, not quickly.

It helps readability, but it is not essential to the grammar.

Japanese commas often show a pause or make the structure easier to follow. The sentence would still be grammatical without it:

• 朝早く支度して昼までに家に戻るつもりだ。

The comma simply makes the linked actions easier to read.