Learn Hardcore Korean: uri samusireun 3cheunge isseoyo.

Because 우리 사무실 is treated as one noun phrase where 우리 serves as a determiner (“our”) modifying 사무실 (“office”). You only need a topic marker (은) on 사무실, not on 우리 itself.

What does the particle 은 do in 사무실은?

은 marks 사무실 as the topic of the sentence. It highlights “our office” as what you’re talking about. Note that if a noun ends in a vowel you’d use 는 instead, but because 사무실 ends in a consonant (ㄹ), you attach 은.

Why is it 3층 and not using native Korean numbers?

Korean floors almost always use Sino-Korean numbers (일, 이, 삼, …) plus 층. So “third floor” is 삼층, often written with a digit as 3층. Native Korean numbers (like 하나, 둘) aren’t normally used with 층.

What role does the particle 에 play in 3층에?

에 is the location particle indicating where something exists or happens. Here, 3층에 means “on the third floor,” marking the place where the office is.

How does 있어요 work in this sentence?

있어요 is the polite informal present form of 있다, which here means “to exist” or “to be located.” With 장소 + 에, it describes location: “X is at Y.” If you want to express possession, you’d use 있어요 with 이/가 after the possessor (e.g., 저에게 시간이 있어요 “I have time”).

Why is 있어요 in the polite form and not 있습니다?

Korean has different speech levels. 있어요 is polite informal (해요체), suitable for everyday conversation. 있습니다 is polite formal (합쇼체), used in presentations, news broadcasts, or very formal settings.

Can you use 저희 사무실은 instead of 우리 사무실은?

Yes. 우리 is the general word for “our” and is widely used even in polite contexts. 저희 is a humble form of “we/our” that shows extra respect to the listener. In a strictly formal business email or announcement, you might choose 저희 사무실은 3층에 있습니다.