Bạn có biết hiệu thuốc nào còn mở không? Tôi cần mua thuốc bây giờ.

Bạn is a common way to say you in Vietnamese, especially when speaking to:

• a friend
• someone around your age
• someone in an informal but polite situation

It is not the only word for you. Vietnamese uses different pronouns depending on age, relationship, and social context. For example:

• anh for an older male
• chị for an older female
• em for a younger person
• cô / chú / bác for older adults

So Bạn có biết... is grammatically fine and widely understood, but in real life, Vietnamese speakers often choose a more relationship-specific pronoun.

This is a very common Vietnamese way to make a yes-no question.

The pattern is:

• subject + có + verb + không?

So:

• Bạn có biết không? = Do you know?

In your sentence, the object of biết is longer:

• Bạn có biết hiệu thuốc nào còn mở không?

That literally works like:

• You have know pharmacy which still open not?

More natural English structure is different, but in Vietnamese this pattern is very normal.

That final không closes the có ... không question pattern.

Even though there is a long phrase in the middle, the structure is still:

• Bạn = subject
• có biết = do know
• hiệu thuốc nào còn mở = any pharmacy that is still open
• không = question marker completing the yes-no pattern

So the final không does not mean no by itself here. It marks the sentence as a yes-no question.

Nào here means which or any depending on context.

In this sentence:

• hiệu thuốc nào còn mở means which pharmacy is still open or any pharmacy that is still open

It is used to ask for an unspecified item from a group.

A useful comparison:

• hiệu thuốc nào? = which pharmacy?
• có hiệu thuốc nào không? = is there any pharmacy?

So nào often helps express the idea of which one / any one.

Còn often means still.
Mở means open.

So còn mở means still open.

That is very natural in Vietnamese when asking whether a shop, restaurant, or pharmacy has not closed yet.

Examples:

• Cửa hàng còn mở không? = Is the shop still open?
• Ngân hàng còn mở không? = Is the bank still open?

This is slightly different from just mở, because còn mở suggests that time matters and you are wondering whether it has remained open until now.

Hiệu thuốc is correct and understandable, but in modern everyday Vietnamese, nhà thuốc is often more common.

Both can mean pharmacy / drugstore.

• hiệu thuốc = an older or more traditional-sounding term
• nhà thuốc = very common in modern usage

You may also see:

• tiệm thuốc
• quầy thuốc

These can vary a bit by region and type of business.

So the sentence is fine, but many speakers today might say:

• Bạn có biết nhà thuốc nào còn mở không?

Both are possible, but they mean slightly different things.

• Bạn có biết hiệu thuốc nào còn mở không?
  = Do you know any pharmacy that is still open?

This asks about the listener’s knowledge.

• Có hiệu thuốc nào còn mở không?
  = Is there any pharmacy still open?

This asks more directly about whether such a pharmacy exists.

So biết adds the idea do you know rather than simply is there.

Vietnamese often puts descriptive information after the noun.

So:

• hiệu thuốc = pharmacy
• nào = which / any
• còn mở = still open

Together:

• hiệu thuốc nào còn mở = which pharmacy is still open or any pharmacy that is still open

This is normal Vietnamese noun phrase structure. English often uses relative clauses with that is:

• a pharmacy that is still open

Vietnamese usually does not need a word like that is here.

Not exactly.

In hiệu thuốc, the word thuốc is part of the compound meaning pharmacy / drugstore.

In mua thuốc, thuốc means medicine.

So the same word appears in two related but different ways:

• hiệu thuốc = pharmacy
• thuốc = medicine

This is very common in Vietnamese, where one word can appear by itself or inside a compound with a more specific meaning.

Bây giờ means now / right now.

Putting time expressions at the end of the sentence is very common in Vietnamese:

• Tôi cần mua thuốc bây giờ. = I need to buy medicine now.

You can sometimes move time expressions earlier for emphasis, but the end position is very natural.

For example:

• Bây giờ tôi cần mua thuốc.
• Tôi cần mua thuốc bây giờ.

Both are correct, but the second one sounds very straightforward and natural.

Tôi is a safe, neutral, polite word for I. It works well in many situations, especially with people you do not know well.

However, in everyday speech, Vietnamese speakers often match the first-person pronoun to the relationship, just like with you words. For example:

• mình with close friends
• em when speaking to someone older
• anh / chị when referring to yourself with someone younger

So Tôi cần mua thuốc bây giờ is correct and polite, but in real conversation many speakers would choose a more context-specific pronoun.

Yes. The sentence is correct, but in real life speakers often soften it a little or use relationship-based pronouns.

Some natural alternatives are:

• Bạn biết nhà thuốc nào còn mở không?
• Bạn có biết nhà thuốc nào còn mở không?
• Xin lỗi, bạn có biết nhà thuốc nào còn mở không? Tôi cần mua thuốc ngay bây giờ.

Notes:

• Xin lỗi at the beginning makes it more polite when asking a stranger.
• ngay bây giờ sounds stronger than bây giờ, more like right now.
• nhà thuốc may sound more modern than hiệu thuốc.

So the original sentence is good Vietnamese, but there are several natural variations depending on tone and situation.