zhège zhǐxiāng hái hěn wánhǎo.

In Mandarin, adjectives can often act as the predicate by themselves, so you usually do not use 是 before them.

So:

• 这个纸箱还很完好 = This box is still quite intact / still in good condition

But:

• 这个纸箱是很完好 sounds unnatural in normal speech

A good basic rule is:

• before nouns, 是 is common
  
  • 他是老师
• before adjectives, 是 is usually not used
  
  • 他很高
  • 纸箱很完好

So here, 完好 is doing the job that intact / in good condition does in English.

Here 还 means still.

So 这个纸箱还很完好 means the box is still in good condition or is still intact.

This often suggests that the speaker may have expected damage, but the box remains fine anyway.

For example:

• 纸箱还很完好 = The box is still in good shape
• 他还在家 = He is still at home

In other contexts, 还 can also mean also, so learners often get confused. In this sentence, though, still is the correct meaning.

Because 还 has more than one pronunciation and meaning:

• hái = still, also
• huán = to return, give back

In this sentence, it means still, so it is pronounced hái.

Examples:

• 我还没吃饭 → hái = I still haven’t eaten
• 还书 → huán = return a book

So in 这个纸箱还很完好, the pronunciation is hái.

很 often appears before adjectives in Mandarin, even when English would not say very.

So 很 does not always strongly mean very. Sometimes it just makes the sentence sound natural when an adjective is the predicate.

Here:

• 很完好 can mean quite intact, in good condition, or just a natural adjectival statement
• with 还 in front, the whole sentence feels like is still quite intact / still in good shape

If you remove 很:

• 这个纸箱还完好

this can be understood, but it sounds a bit more formal, literary, or less natural in everyday conversation.

So 很 is very common here.

完好 means intact, undamaged, or in good condition.

It is more specific than 好.

• 好 = good, fine, nice
• 完好 = not broken, not damaged, still complete

So:

• 这个纸箱很好 could mean the box is good, nice, useful, or of good quality
• 这个纸箱很完好 specifically means the box is not damaged and is still intact

That is why 完好 is a better word here than just 好.

In 这个纸箱, the 个 is already the measure word.

Breakdown:

• 这 = this
• 个 = general measure word
• 纸箱 = cardboard box / carton

So 这个纸箱 literally works like this + measure word + box.

You do not add another measure word after 这个. It is already complete.

A learner might wonder whether it should be something like 这一个纸箱. That is possible in some contexts, but:

• 这个纸箱 is the normal everyday form
• 这一个纸箱 sounds more emphatic, like this one box

The sentence follows a very common Mandarin pattern:

Subject + adverb + degree word + adjective

So here:

• 这个纸箱 = subject
• 还 = adverb
• 很 = degree word
• 完好 = adjective / predicate

So the structure is:

这个纸箱 / 还 / 很 / 完好

In natural English, this becomes:

• This cardboard box is still in good condition
• This box is still quite intact

Mandarin usually places adverbs like 还 before the adjective or verb they modify.

Yes, you can.

• 纸箱 specifically means paper box / cardboard box / carton
• 箱子 is a more general word for box, case, chest, trunk

So:

• 这个纸箱还很完好 = This cardboard box is still in good condition
• 这个箱子还很完好 = This box is still in good condition

If you want to emphasize that it is made of cardboard, 纸箱 is better.

Often, yes.

Because of 还, the sentence can carry the feeling of:

• even now, it’s still intact
• surprisingly, it’s still in good condition

So depending on context, it may imply that the box has been used, moved, shipped, or stored for some time, yet it remains fine.

For example, after a long delivery or after finding an old box, saying:

• 这个纸箱还很完好

can sound like:

• This box is actually still in pretty good shape

Not exactly.

• 纸箱 usually means a cardboard box or carton
• 盒子 usually means a box/container, often smaller, and not necessarily cardboard

Examples:

• shipping box → 纸箱
• gift box → often 盒子
• storage box → could be 箱子 or another specific word depending on the type

So in this sentence, 纸箱 strongly suggests a cardboard box, especially the kind used for packing or shipping.