dào xīnjū yǐhòu zài chāixiāng.

Here 到 means to arrive at or to reach.

So 到新居以后 means after arriving at the new home.

In this sentence, 到 is part of the action that happens first, and 拆箱 is the action that happens later.

In Mandarin, 以后 usually comes after the whole word or phrase that it refers to.

So:

到新居以后 = after arriving at the new home

It is not just modifying 新居 by itself. It is attached to the whole idea 到新居.

A useful pattern is:

[event / time] + 以后 = after [event / time]

Examples:

• 吃饭以后 = after eating
• 下课以后 = after class
• 到新居以后 = after arriving at the new home

Yes, 到了新居以后 is also correct.

Both are natural, but they feel slightly different:

• 到新居以后再拆箱: more neutral, often used in instructions or plans
• 到了新居以后再拆箱: emphasizes that the arrival is completed first

In many everyday sentences, Mandarin does not need 了 if the sequence is already clear from context.

Here 再 means something like then, after that, or only then.

It shows sequence:

1. first arrive at the new home
2. then unpack

So 再拆箱 does not mainly mean unpack again here. It means unpack later, after the first step.

This is a very common learner question.

In simple terms:

• 再 is often used for something that will happen later or next
• 又 is often used for something that has already happened again, or for repeated situations

In this sentence, unpacking is a later action, so 再 is the right choice.

Compare:

• 到新居以后再拆箱 = Unpack after arriving at the new home
• 又拆箱了 = unpacked again

So 再 fits the future sequence here.

拆箱 literally means open boxes or unpack boxes.

• 拆 = to open up, take apart, undo
• 箱 = box, case, trunk

In a moving context, 拆箱 means to unpack. It can also be used for unboxing products, especially online.

So in this sentence, it means unpacking the moving boxes after arriving at the new home.

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

So this sentence could mean different things depending on the situation:

• We’ll unpack after we get to the new home
• Unpack after you get to the new home
• Let’s unpack after arriving at the new home

The subject is omitted because the listener usually already knows who is involved.

It can be any of those, depending on context and tone of voice.

Without a subject, Mandarin often allows this kind of flexibility.

For example, it could be:

• a plan: We’ll unpack after we get to the new place
• a suggestion: Let’s unpack after we get there
• an instruction: Don’t unpack until you arrive at the new home

The grammar itself does not force only one interpretation.

新居 is understandable and natural, but it is a bit more formal or polished than 新家.

Roughly speaking:

• 新居 = new residence, new home; slightly formal or elegant
• 新家 = new home; more everyday
• 新房子 = new house/apartment; focuses more on the building itself

So 到新居以后再拆箱 sounds a little more polished than 到新家以后再拆箱.

Mandarin often puts the background or earlier event first, and the main action later.

So the structure is:

到新居以后 + 再 + 拆箱
after arriving at the new home + then + unpack

A good way to think about it is:

[After X] + [then do Y]

That is a very common Mandarin pattern.

Yes, absolutely.

搬到新居以后再拆箱 is also natural, and it makes the meaning a bit more explicit:

• 到新居以后 = after arriving at the new home
• 搬到新居以后 = after moving into the new home

So adding 搬 emphasizes the move itself. The original sentence is shorter and still sounds natural if the moving context is already clear.