Bìa các tông đang khô ráo.

Vietnamese often does not use a verb like to be before adjectives.

So where English says:

• The cardboard is dry

Vietnamese can simply say:

• Bìa các tông khô ráo

or, in your sentence,

• Bìa các tông đang khô ráo

Here, khô ráo is the description, and Vietnamese does not need a separate is before it.

A useful rule:

• with nouns: A là B can mean A is B
• with adjectives/states: usually no là

For example:

• Anh ấy là bác sĩ = He is a doctor
• Anh ấy mệt = He is tired

Đang marks something as being true right now or as an ongoing current situation.

So in this sentence, it adds the idea that the cardboard is currently dry.

Compare:

• Bìa các tông khô ráo = The cardboard is dry.
• Bìa các tông đang khô ráo = The cardboard is dry right now / is currently dry.

With verbs, đang often works like be + -ing:

• Tôi đang ăn = I am eating

With adjectives or states, it can emphasize the present condition:

• Trời đang lạnh = It is cold right now

So yes, đang is possible here, though in some contexts it may sound slightly more marked than simply leaving it out.

Both relate to dryness, but khô ráo usually sounds a bit more like:

• dry and not damp
• nicely dry
• free from moisture

So:

• khô = dry
• khô ráo = dry, thoroughly dry, not at all damp

For objects, weather, rooms, floors, clothes, paper, etc., khô ráo often feels more natural when you want to stress that something is in a good, dry condition.

Examples:

• Quần áo đã khô = The clothes are dry.
• Sàn nhà khô ráo = The floor is dry and not slippery/damp.

Yes, bìa các tông is a normal expression meaning cardboard.

Roughly:

• bìa = board, stiff paper, cover
• các tông = a loanword related to carton/cardboard

Together, bìa các tông functions as one noun phrase meaning cardboard.

Learners should usually understand it as a set phrase rather than trying to translate each part too literally every time.

Yes. Like most Vietnamese nouns, bìa các tông does not change form for singular or plural.

Depending on context, it can mean:

• cardboard in general
• a piece of cardboard
• pieces of cardboard

If you want to make the quantity clearer, you add a number word or classifier-like noun:

• một tấm bìa các tông = one sheet/piece of cardboard
• hai miếng bìa các tông = two pieces of cardboard

So the bare phrase bìa các tông is number-neutral.

The sentence follows a very common Vietnamese pattern:

• subject + time/aspect word + adjective/state

So here:

• Bìa các tông = subject
• đang = marks the current situation
• khô ráo = state/adjective

This is normal Vietnamese word order.

You should not move khô ráo in front of the noun the way English sometimes does with adjectives. Vietnamese descriptive adjectives in sentences usually come after the subject as part of the predicate.

Yes, absolutely.

That version is often the more neutral one:

• Bìa các tông khô ráo = The cardboard is dry.

Adding đang emphasizes that this is the cardboard’s current condition:

• Bìa các tông đang khô ráo = The cardboard is currently dry.

So both are possible, but đang adds a little extra focus on right now.

Each syllable has its own tone:

• bìa – low/falling tone on bìa
• các – rising tone
• tông – level tone
• đang – level tone
• khô – level tone
• ráo – rising tone

A rough English-style guide would be something like:

bee-uh kak tong dang khoh ráo

But that is only approximate. The tones matter a lot more than English spelling can show.

A few pronunciation notes:

• đ is not the same as English d; it is a voiced d sound
• kh is like a breathy k sound, somewhat similar to the ch in German Bach or Scottish loch
• bìa has two vowel parts together, not just a simple bee

If you want to sound natural, it is best to learn the whole phrase by listening and repeating rather than relying on English approximation.

Yes, it is understandable and natural.

It would fit contexts like:

• checking whether cardboard is usable
• describing storage conditions
• saying something is not wet anymore

For example, after rain or after moving materials:

• Bìa các tông đang khô ráo, dùng được rồi. = The cardboard is dry now, so it can be used.

If you just want the simplest everyday statement, many speakers might also say:

• Bìa các tông khô rồi. = The cardboard is dry now/already dry.
• Bìa các tông khô ráo rồi. = The cardboard is dry now and no longer damp.

So your sentence is fine; it just has a slightly explicit currently dry feel because of đang.