wǒmen bùshì xiān chāixiāng, jiùshì xiān ānzhuāng jiājù.

It is a very common pattern meaning either A, or B.

So in this sentence:

• 不是先拆箱
• 就是先安装家具

the speaker is saying there are two possible orders: either unpack first, or assemble/install the furniture first.

Not really. In this pattern, they work together as a set expression.

• 不是 does not simply mean is not
• 就是 does not simply mean is exactly

Instead, 不是 A，就是 B should be understood as one grammar structure: either A or B.

Because each option has its own first.

• 先拆箱 = unpack first
• 先安装家具 = assemble/install the furniture first

Repeating 先 makes the two choices balanced and clear. This is very natural in Mandarin.

No. Even though 不是 usually has a negative meaning, in 不是 A，就是 B the whole pattern is not negative.

It is just presenting two alternatives. So this sentence is not saying we are not unpacking first. It is saying the first step will be one of these two things.

Yes, sometimes.

Depending on context and tone of voice, it can mean:

• neutral: either A or B
• slightly annoyed: it’s always either A or B

In your sentence, without extra context, it sounds neutral: the speaker is just talking about two possible action orders.

Usually no. 不是……就是…… is mainly for making a statement.

If you want to ask Which one should we do first?, a more natural sentence is:

我们是先拆箱，还是先安装家具？

Here, 还是 is the normal word for or in this kind of question.

Not inside this exact pattern.

• 不是 A，就是 B is a fixed expression
• 或者 is a more general word for or

So you should not mix them like this:

• 不是 A，或者 B ← unnatural here

If you want a different structure, you can use something like:

• 要么先拆箱，要么先安装家具
• 我们是先拆箱，还是先安装家具？

They are related, but not identical.

• 打开箱子 = open the box
• 拆箱 = unbox, often meaning opening the packaging and taking things out

So 拆箱 is more specific and often used for packages, deliveries, and new products.

It means something like install furniture or assemble furniture, depending on context.

In everyday use, 安装 often suggests setting something up properly, possibly putting parts together and putting it in place.

A related word is 组装家具, which more clearly emphasizes assembling furniture from parts. In many situations, the two can overlap.

Because 家具 is a collective noun, much like furniture in English.

You normally do not add a plural ending to it. It can refer to furniture in general, whether one piece or several pieces.

If you want to count items, you can say things like:

• 一件家具 = one piece of furniture
• 几件家具 = several pieces of furniture

That is because of tone sandhi.

The word 不 is normally fourth tone, but before another fourth-tone syllable, it changes to second tone in pronunciation.

So:

• underlying form: bù shì
• actual common pronunciation: búshì

This is completely normal in spoken Mandarin.

The overall frame is fixed:

不是 + option A，就是 + option B

But you can change which option comes first:

• 我们不是先拆箱，就是先安装家具
• 我们不是先安装家具，就是先拆箱

Both are grammatical, but the emphasis changes slightly because the first option mentioned comes first in the listener’s mind.