Bạn có nhớ tôi đã để điện thoại ở đâu không?

Here bạn means you.

It is a very common Vietnamese pronoun, but it is not the only way to say you. Vietnamese pronouns depend a lot on age, relationship, and social context. Bạn is relatively neutral and often used:

• with friends
• with classmates or coworkers
• when speaking politely but not very formally
• in textbook Vietnamese

In real life, a speaker might use other pronouns instead, such as anh, chị, em, cô, chú, and so on, depending on who they are talking to.

Có ... không? is a very common way to form a yes/no question in Vietnamese.

So:

• Bạn có nhớ không? = Do you remember?
• Bạn nhớ không? can also be used, and it is natural too

Using có ... không often makes the question structure especially clear for learners. It is similar to marking the sentence as a question, though it does not work exactly like English do/does.

In this sentence:

• có nhớ = remember
• không at the end turns the whole thing into a yes/no question

Tôi is a common Vietnamese pronoun meaning I / me.

Vietnamese pronouns do not change form the way English pronouns do. English has:

• I for subject
• me for object

But Vietnamese uses the same form:

• tôi = I
• tôi = me

So in Bạn có nhớ tôi... không?, tôi means me in English, but the Vietnamese word stays tôi.

Đã usually marks that something happened in the past.

So:

• tôi để điện thoại ở đâu = where I leave / put the phone
• tôi đã để điện thoại ở đâu = where I left / put the phone

In this sentence, đã helps show that the action of putting the phone somewhere happened earlier.

However, Vietnamese tense is more flexible than English tense. Speakers do not always have to mark the past if the context already makes it clear. So sometimes you may also hear:

• Bạn có nhớ tôi để điện thoại ở đâu không?

That can still mean Do you remember where I left the phone? if the context is clear.

Here để means to leave or to put something somewhere.

In this sentence:

• để điện thoại ở đâu = leave/put the phone where

So the meaning is about the location where the speaker placed the phone.

Be careful: để has several meanings in Vietnamese depending on context. It can also mean things like:

• in order to
• let
• leave something as it is

But in this sentence, the meaning is clearly put/leave.

Ở đâu means where.

Vietnamese often keeps the basic sentence order and puts the question word in the place where the missing information belongs.

So:

• Tôi đã để điện thoại ở đâu. = I left the phone where.
  This is the Vietnamese structure.

In natural English, we move where to the front:

• where I left the phone

But Vietnamese usually does not front question words in the same way. That is why:

• tôi đã để điện thoại ở đâu literally looks like
• I left the phone at where

This is very normal Vietnamese word order.

That is a great question because this sentence contains a question inside another question.

The main question is:

• Bạn có nhớ ... không?
• Do you remember ... ?

Inside that main yes/no question, there is an embedded clause:

• tôi đã để điện thoại ở đâu
• where I left the phone

So không belongs to the main question, not to ở đâu.

Compare:

• Bạn có nhớ tôi đã để điện thoại ở đâu không? = Do you remember where I left my phone?

The speaker is not directly asking Where did I leave my phone?
The speaker is asking whether you remember that information.

Word-for-word, it is closer to that structure, yes. But that is not natural English.

A rough breakdown is:

• Bạn = you
• có nhớ = do remember / remember
• tôi = I / me
• đã để = left / put
• điện thoại = phone
• ở đâu = where
• không = question marker

Natural English restructures it as:

• Do you remember where I left my phone?

So the Vietnamese and English grammar are organized differently, even though the meaning matches.

Vietnamese often omits possessive words like my, your, his, and so on when the meaning is obvious from context.

Here, because the speaker says:

• tôi đã để điện thoại ở đâu it is easy to understand that the phone is probably my phone.

So:

• điện thoại = phone / the phone
• in context, it naturally becomes my phone in English

If the speaker wanted to make possession explicit, they could say:

• điện thoại của tôi = my phone

So a fuller version would be:

• Bạn có nhớ tôi đã để điện thoại của tôi ở đâu không?

But that often sounds unnecessary because the shorter version is more natural.

It is very close here, but nhớ has a broader range of meaning than English remember.

Depending on context, nhớ can mean:

• remember
• miss someone
• keep in mind

Examples:

• Tôi nhớ rồi. = I remember now.
• Tôi nhớ bạn. = I miss you.
• Nhớ làm bài nhé. = Remember to do your homework.

In this sentence, nhớ clearly means remember.

Yes. Vietnamese often allows shorter versions when the context is clear.

Some natural alternatives are:

• Bạn nhớ tôi để điện thoại ở đâu không?
• Bạn có nhớ tôi để điện thoại đâu không?
• Bạn nhớ mình để điện thoại ở đâu không?

A few notes:

• dropping đã is common if the past is obvious
• dropping có can sound a bit more conversational
• mình may be used instead of tôi in more informal or friendly speech

The original sentence is very clear and perfectly good Vietnamese, especially for learners.

It is fairly neutral.

Why?

• bạn is a common neutral you
• tôi is a common neutral I
• the grammar is standard and polite

It does not sound extremely formal, but it is more neutral and textbook-like than very intimate everyday speech between close friends or family.

For close friends, people might choose different pronouns or more casual wording. For example:

• Cậu có nhớ tớ để điện thoại ở đâu không?
• Mày có nhớ tao để điện thoại ở đâu không?
  This one is much rougher and depends heavily on relationship, so learners should be careful with it.

So the original sentence is a safe, standard choice.