क्या आपको बहन का नया ऑफिस याद है?

A helpful rough breakdown is:

• क्या = marks a yes/no question
• आपको = to you
• बहन का नया ऑफिस = sister’s new office
• याद है = is remembered / is in memory

So the sentence is built more like:

Is sister’s new office remembered to you?

That sounds unnatural in English, but it helps explain why Hindi uses आपको and याद है here.

At the beginning of a sentence, क्या usually turns it into a yes/no question.

• आपको बहन का नया ऑफिस याद है। = You remember your sister’s new office.
• क्या आपको बहन का नया ऑफिस याद है? = Do you remember your sister’s new office?

Hindi can sometimes ask yes/no questions just by intonation, but sentence-initial क्या is very common and very clear.

Because Hindi does not say remember the same way English does.

With याद है, the person who remembers is usually marked with को:

• मुझे याद है = I remember
• तुम्हें याद है = you remember
• आपको याद है = you remember (polite)

So आपको literally means to you, and this is the normal Hindi pattern with याद.

In Hindi, याद is used in a stative expression, not like the ordinary English verb to remember.

So:

• मुझे वह बात याद है। = I remember that thing.
• literally: That thing is in my memory / remembered to me.

In your sentence, याद है means something like is remembered or is in memory. This is why the sentence does not look like a direct translation of English grammar.

Because का / की / के agrees with the thing possessed, not with the possessor.

Here, the possessed thing is ऑफिस, which is treated as masculine singular, so Hindi uses का:

• बहन का ऑफिस = sister’s office

Compare:

• बहन की कार = sister’s car
  because कार is feminine
• बहन के दोस्त = sister’s friends
  because दोस्त is plural

So का matches ऑफिस, not बहन.

Yes, from an English point of view, it may feel omitted.

Hindi often leaves kinship words like mother, father, brother, sister without an explicit possessive when the relationship is already clear from context.

So बहन का नया ऑफिस can naturally mean:

• your sister’s new office
• his/her sister’s new office
• just sister’s new office

If you want to make it completely explicit, you can say:

क्या आपको आपकी बहन / आपकी बहन का नया ऑफिस याद है?

But in normal speech, Hindi often omits that possessive if it is obvious.

Because ऑफिस is usually treated as a masculine noun in Hindi, so the adjective also takes the masculine singular form:

• नया ऑफिस = new office

If the noun were feminine, you would use नई:

• नई कार = new car

So नया agrees with ऑफिस.

It is a borrowed word from English, but it behaves like a Hindi noun in the sentence.

That means it can take:

• Hindi postpositions
• Hindi possessive agreement
• Hindi adjective agreement

So even though ऑफिस comes from English, Hindi still treats it grammatically like a noun inside the language.

Because Hindi does not have articles like English a/an/the.

So ऑफिस can mean:

• an office
• the office

Context tells you which one is meant. In this sentence, context makes it feel like the new office.

Not completely. Hindi word order is fairly flexible, though some versions sound more natural than others.

The given sentence is very natural:

क्या आपको बहन का नया ऑफिस याद है?

You may also hear:

• आपको बहन का नया ऑफिस याद है क्या?
  This also asks a yes/no question, but it feels more conversational.

The core idea is that आपको and याद है stay in a natural relationship, and बहन का नया ऑफिस stays together as a noun phrase.

You can, but it changes the feel.

• याद है = do you remember / is it in your memory?
• याद करना = to remember, to think of, to recall, sometimes even to miss

For this sentence, याद है is the most natural way to ask whether someone remembers something already known.

For example:

• क्या आपको बहन का नया ऑफिस याद है? = Do you remember your sister’s new office?
• आप बहन का नया ऑफिस याद करते हैं sounds less natural for this exact meaning.

So for simple Do you remember X?, X याद है is usually the safer pattern.

आपको is the polite/respectful form of you.

Other versions would be:

• तुम्हें बहन का नया ऑफिस याद है? = informal/friendly
• तुझे बहन का नया ऑफिस याद है? = very informal, intimate, or sometimes rude depending on context

So the original sentence is addressing someone politely.

You normally put नहीं before है:

क्या आपको बहन का नया ऑफिस याद नहीं है?
= Don’t you remember your sister’s new office?

Or as a statement:

मुझे बहन का नया ऑफिस याद नहीं है।
= I don’t remember my sister’s new office.

So the basic pattern is:

[person + को] + [thing] + याद नहीं है