Khi mạng chậm, tôi không thể kiểm tra xem đơn hàng có bị mất hay không.

Khi means when. It introduces a time clause:

• Khi mạng chậm = When the network is slow

In Vietnamese, this time clause can come before the main clause, just like in English:

• Khi mạng chậm, tôi không thể... = When the network is slow, I can’t...

You may also sometimes see lúc or khi... thì..., but khi alone is very common and natural here.

In Vietnamese, adjectives often come directly after the noun without a verb like to be.

So:

• mạng chậm = the network is slow
• literally: network slow

This is very normal in Vietnamese. The verb là is usually not used before adjectives in sentences like this.

Compare:

• Mạng chậm. = The network is slow.
• Đơn hàng quan trọng. = The order is important.

So mạng chậm is the natural structure.

Không thể means cannot / be unable to.

In this sentence:

• tôi không thể kiểm tra = I cannot check

Breakdown:

• không = not
• thể = ability/possibility in this structure

So không thể + verb is a common way to say that something is not possible.

Examples:

• Tôi không thể đi. = I can’t go.
• Cô ấy không thể mở file. = She can’t open the file.

This is a very common Vietnamese pattern.

• kiểm tra = to check
• xem here helps introduce what you are checking, almost like to see whether

So:

• kiểm tra xem đơn hàng có bị mất hay không
• = check to see whether the order has been lost or not

If you only said kiểm tra đơn hàng, that would mean check the order, but it would not express the full idea of check whether...

So kiểm tra xem... is a very natural way to say check whether / check to see if.

Yes, it is the same word, but here it has a different function.

You may already know:

• xem TV = watch TV
• xem phim = watch a movie
• xem = look / watch / see

But after verbs like kiểm tra, xem often means something like to see whether / to find out whether.

So in this sentence, xem does not literally mean watch. It helps connect check with the information being checked.

Đơn hàng means order, especially a purchase order or delivery order.

Breakdown:

• đơn = form / application / order document
• hàng = goods / merchandise

Together, đơn hàng means a customer order, such as something bought online.

So:

• kiểm tra xem đơn hàng... = check whether the order...

This is a very important Vietnamese pattern for whether ... or not.

In the sentence:

• đơn hàng có bị mất hay không
• = whether the order has been lost or not

Pattern:

• có + verb/adjective + hay không
• = whether + verb/adjective + or not

Examples:

• Tôi không biết anh ấy có đến hay không. = I don’t know whether he is coming or not.
• Cô ấy hỏi trời có mưa hay không. = She asked whether it was raining or not.

So here, có ... hay không frames the yes/no uncertainty.

No. In this sentence, có does not mean to have.

Here it is part of the pattern:

• có ... hay không = whether ... or not

So in:

• đơn hàng có bị mất hay không

the có is not possession. It is a grammatical marker used in an indirect yes/no question.

This is different from:

• Tôi có một đơn hàng. = I have an order.

Same word, different function.

Both are possible in some contexts, but bị mất adds an idea of something bad happening to the order.

• mất = lost / missing
• bị mất = be lost / get lost, often with a negative or unwanted sense

The word bị is often used when something undesirable happens to the subject.

So:

• đơn hàng bị mất = the order got lost / the order was lost

This sounds very natural because losing an order is an unfortunate event.

If you said just đơn hàng mất, it might be understood in context, but bị mất is clearer and more standard here.

Often, yes, but it is not exactly the same as the English passive in every situation.

Bị commonly marks that the subject is affected by something negative or unwanted.

Examples:

• Tôi bị ốm. = I got sick.
• Xe bị hỏng. = The vehicle is broken / got broken.
• Đơn hàng bị mất. = The order was lost / got lost.

So you can think of bị as something like a passive or affected-subject marker, especially for bad situations.

There is also được, which is often used for positive or beneficial situations:

• Tôi được khen. = I was praised.

Sometimes yes, but it changes the feel slightly.

You may hear:

• kiểm tra xem đơn hàng có bị mất không

This is very common in everyday speech and means the same thing: check whether the order is lost.

The longer form:

• có bị mất hay không

is a bit fuller and more explicit: whether it is lost or not.

So both are natural, but:

• có ... hay không = slightly more complete/formal
• có ... không = very common in conversation

The sentence breaks down like this:

• Khi mạng chậm, = When the network is slow,
• tôi không thể = I cannot
• kiểm tra xem = check to see
• đơn hàng có bị mất hay không. = whether the order has been lost or not.

So the overall structure is:

• [Time clause], [subject] + [cannot] + [check to see] + [whether-clause].

That makes the sentence very natural and logical in Vietnamese.

Not very naturally. A word-for-word translation would sound awkward.

Very literal:

• When network slow, I not-can check see order whether be lost or not.

Natural English:

• When the network is slow, I can’t check whether the order has been lost.
• When the network is slow, I can’t check to see whether the order is missing.

This is a good reminder that Vietnamese often uses compact structures like:

• mạng chậm
• kiểm tra xem
• có ... hay không

which should be understood as patterns, not translated one word at a time.