wǒ jīntiān rùzhù, míngtiān tuìfáng.

In Mandarin, time words usually come before the verb.

So the basic pattern is:

Subject + Time + Verb

That is why you get:

• 我今天入住 = I check in today
• 明天退房 = check out tomorrow

Putting 今天 after the verb would usually sound unnatural in a simple sentence like this.

Mandarin often omits words that are already understood from context.

In this sentence, the subject 我 is clear from the first part:

• 我今天入住
• (我)明天退房

So the second 我 is left out because it would be repetitive. This is very common in Chinese.

You could still say:

我今天入住，我明天退房。

That is grammatically fine, but it sounds a bit less smooth unless you want extra emphasis.

Not exactly.

• 住 means to live / to stay / to reside
• 入住 means to check in / to move into a place

So in a hotel context:

• 入住 = check in
• 住 = stay

For example:

• 我今天入住。 = I’m checking in today.
• 我住两晚。 = I’m staying for two nights.

入住 sounds more specific and more natural for hotels, apartments, or formal lodging situations.

退房 means to check out (of a hotel).

Literally:

• 退 = return / withdraw / check out
• 房 = room

But as a set phrase, 退房 means to vacate the room and complete checkout.

This is a very common hotel word. In English, we say check out; in Mandarin, the usual hotel expression is 退房.

Yes. In hotel situations, the place is often understood from context, so you do not need to say it explicitly.

For example:

• 今天入住，明天退房。
• 我想下午入住。
• 请问几点退房？

If needed, you can make it explicit:

• 入住酒店 = check into the hotel
• 从酒店退房 = check out of the hotel

But in many real conversations, just 入住 and 退房 are enough.

Yes. It sounds natural, especially in a hotel, booking, or front-desk context.

It is a concise statement meaning something like:

• I’m checking in today and checking out tomorrow.

Mandarin often prefers this kind of compact, context-based phrasing, especially when the situation is already obvious.

Yes, you can. That is grammatical.

Here are some common versions:

• 我今天入住，明天退房。
• 今天我入住，明天我退房。
• 我今天入住，明天我退房。

The differences are mainly about focus and rhythm:

• 我今天入住，明天退房。
  Very natural, neutral, concise.

• 今天我入住，明天我退房。
  Slightly more emphasis on the time words today and tomorrow.

• 我今天入住，明天我退房。
  Also fine, but repeating 我 is often unnecessary.

The comma separates two related parts:

• 我今天入住
• 明天退房

It works a bit like and in English, but Mandarin often just places the actions side by side without adding a word for and.

So:

我今天入住，明天退房。

naturally means:

I check in today, and I check out tomorrow.

The comma shows a pause and helps the sentence read clearly.

Yes. The tones are:

• 我 wǒ — 3rd tone
• 今天 jīntiān — 1st tone + 1st tone
• 入住 rùzhù — 4th tone + 4th tone
• 明天 míngtiān — 2nd tone + 1st tone
• 退房 tuìfáng — 4th tone + 2nd tone

A few tips:

• 入住 rùzhù has two strong falling tones, so it sounds firm.
• 退房 tuìfáng starts with a falling tone on 退, then rises on 房.
• 我 wǒ is 3rd tone, but in normal speech it is often not pronounced as a full deep dip unless emphasized.

Mostly, yes, especially 退房.

• 退房 is strongly associated with hotels or other short-term lodging.
• 入住 can be used for hotels, but also for moving into an apartment, dorm, or residential complex, depending on context.

So in this sentence, learners will usually understand it as a hotel sentence:

我今天入住，明天退房。

Not very naturally.

A word-for-word breakdown is something like:

• 我 = I
• 今天 = today
• 入住 = check in
• 明天 = tomorrow
• 退房 = check out

So the structure is close to:

I today check in, tomorrow check out.

That helps you understand the grammar, but natural English would be:

I’m checking in today and checking out tomorrow.

So the Mandarin structure is straightforward, but the best English translation is usually smoother than a word-for-word version.