Bị hư hỏng là lý do đổi trả; nên đổi hàng.

Bị often marks that something happens to the subject in an unwanted or negative way.

In bị hư hỏng, it gives the idea of being damaged or having become damaged.

A useful comparison:

• Hàng bị hư hỏng = The goods are damaged / The goods got damaged
• bị adds a negative, affected feeling
• without bị, hư hỏng just describes the state more directly

So here, bị helps express that the item is in a bad condition, not just neutrally describing it.

Hư and hỏng are very similar and both relate to being damaged, broken, or no longer usable.

When they appear together as hư hỏng, they form a common set phrase meaning:

• damaged
• broken
• defective
• in bad condition

This kind of doubling is common in Vietnamese. Sometimes two near-synonyms are paired to create a more fixed, natural expression.

Very roughly:

• hư = damaged, spoiled, bad
• hỏng = broken, malfunctioning

But in real usage, hư hỏng is often best learned as one chunk.

Here, bị hư hỏng acts like a noun-like idea or clause: being damaged.

So the pattern is:

• bị hư hỏng = being damaged / being defective
• là = is
• lý do đổi trả = a reason for return/exchange

So the structure is essentially:

• Being damaged is a reason for return/exchange.

Vietnamese often allows verb phrases or descriptive phrases to stand before là like this.

Literally, it is something like:

• lý do = reason
• đổi trả = exchange/return

Together, lý do đổi trả means:

• a reason for return/exchange
• grounds for returning or exchanging a product

In smoother English, you would usually add a linking idea such as for:

• a reason for return/exchange

Vietnamese often leaves out words that English requires, so this compact structure is normal.

These are related but not exactly the same.

• đổi trả = return or exchange, often as a general store-policy term
• đổi hàng = exchange the goods/item for another one

So:

• lý do đổi trả sounds like a policy/category expression
• nên đổi hàng is more specifically about choosing exchange rather than just talking about the return/exchange process in general

In shopping contexts:

• đổi trả = the whole return/exchange option
• đổi hàng = to swap the item for another item

Vietnamese often omits the subject when it is obvious from context.

So nên đổi hàng could mean things like:

• (You) should exchange the item
• It should be exchanged
• One should exchange the goods

The exact subject depends on context.

This is very common in Vietnamese. If the situation is already clear, speakers do not always say you, we, the customer, or the store explicitly.

It can suggest both ideas, depending on context.

Most commonly here, nên is understood as:

• should
• ought to

So nên đổi hàng = should exchange the goods/item

But historically and in many sentences, nên can also connect ideas with a therefore/so meaning.

Because of that, this part can feel slightly compressed, almost like:

• Since it is damaged, it should be exchanged.

So in this sentence, nên mainly carries the sense of recommendation or logical conclusion.

Hàng is a general word for goods, merchandise, or item(s) in a commercial context.

It is often used when talking about store procedures, customer service, or return policies.

So đổi hàng is a standard retail expression meaning:

• exchange the item
• exchange the goods

If the speaker wanted to be more specific, they could name the object directly, such as:

• đổi áo = exchange the shirt
• đổi sản phẩm = exchange the product

But đổi hàng is a very natural generic phrase in shopping situations.

It is understandable, but it feels somewhat condensed and policy-like rather than conversational.

Why?

• lý do đổi trả sounds like wording from store rules or a form
• the subject is omitted
• the semicolon makes it feel like two short policy statements

A more natural full sentence in everyday Vietnamese might be:

• Hàng bị hư hỏng là lý do được đổi trả.
• Nếu hàng bị hư hỏng thì nên đổi hàng.
• Hàng bị hư hỏng thì có thể đổi trả.

So the original is not wrong, but it reads more like a short written note than relaxed spoken Vietnamese.

The semicolon separates two closely related ideas:

1. Bị hư hỏng là lý do đổi trả
2. nên đổi hàng

It signals a pause stronger than a comma, but not as final as a period.

You can read it as:

• Being damaged is a reason for return/exchange; therefore, the item should be exchanged.

In everyday Vietnamese writing, many people might simply use a comma or split it into two sentences. So the semicolon is mainly a punctuation choice to show a logical connection between the two parts.