Learn Hardcore Korean: doseogwaneun cheonggyeori jal yujidwaeyo. - Cleanliness is well maintained at the library.

It sets 도서관 (the library) as the topic or frame for the sentence: “As for the library, …”. It doesn’t mean the library is the grammatical subject of the verb. The grammatical subject inside the comment is 청결이. The topic marker can also imply contrast (e.g., “At the library, at least…”).

Why is it 청결이 and not 청결을?

Because 유지되다 is a passive verb meaning “to be maintained.” With passives, the thing affected is the subject, so it takes 이/가: 청결이 유지돼요. If you use the active verb 유지하다 (“to maintain”), you’d say 청결을 유지해요 and specify an agent if needed (e.g., 직원들이 청결을 유지해요).

Can I say 도서관이 청결이 잘 유지돼요?

No. That stacks two subjects (도서관이 and 청결이) and sounds unnatural. Say either:

도서관은 청결이 잘 유지돼요. (topic + subject)
도서관이 잘 유지돼요. (meaning “The library is well maintained” more generally)
Or recast actively: 도서관은 직원들이 청결을 잘 유지해요.

What’s the difference between 유지돼요, 유지되어요, and 유지되요?

유지돼요 and 유지되어요 are both standard; 돼요 is just the contraction of 되어요.
유지되요 is a common misspelling and is incorrect in standard Korean. Tip: 되 + 어요 → 돼요.

Why use the passive 유지되다 here? Can I make it active?

Passive is natural when the agent isn’t specified or isn’t important: the focus is on the resulting state. To make it active, add an agent:

직원들이 청결을 잘 유지해요/유지합니다. (The staff maintain cleanliness well.)

What does 잘 mean in this sentence?

Here 잘 means “well/properly/effectively,” not “often.” So 청결이 잘 유지돼요 = “Cleanliness is well maintained.”

Is 청결 the same as 청소 or 깨끗함?

청결: the state/quality of cleanliness (formal/administrative).
청소: the act of cleaning.
깨끗함/깨끗하다: “clean(ne ss)/to be clean,” everyday/pure-Korean. Examples:
청결이 유지돼요 = “Cleanliness is maintained.”
청소가 잘 돼요 = “The cleaning is done well.”
항상 깨끗해요 = “It’s always clean.”

Is the original sentence natural? What’s a more everyday way to say it?

It’s perfectly natural, but slightly formal/announcement-like. Everyday alternatives:

도서관은 항상 깨끗해요.
도서관은 청결 상태가 잘 유지돼요.
If focusing on the cleaning service: 도서관은 청소가 잘 돼요.

Can I say 도서관에서는 instead of 도서관은?

Yes. 도서관에서는 emphasizes the location and often adds a contrastive nuance (“at the library (as opposed to elsewhere)”). Use it when comparing places or highlighting “at the library.”

Where does 잘 go? Is 도서관은 잘 청결이 유지돼요 okay?

Put 잘 right before the verb it modifies. Say:

도서관은 청결이 잘 유지돼요.
Or simply 도서관은 잘 유지돼요 (if context makes it clear what is maintained). Avoid 잘 청결이 유지돼요.

What politeness level is -돼요, and what’s a more formal version?

-돼요 is polite informal (해요체).
Formal polite: -됩니다 → 도서관은 청결이 잘 유지됩니다.
Casual: 유지돼.

How do I say it’s not maintained well or emphasize continuity?

Negative: 청결이 잘 유지되지 않아요.
Progressive/ongoing: 청결이 잘 유지되고 있어요 (emphasizes it’s being maintained right now).
General/habitual fact: 청결이 잘 유지돼요.

How do you pronounce 돼요? Is 되요 acceptable?

돼요 is pronounced roughly “dweh-yo.” 되요 is not standard spelling. Write 돼요 or 되어요.

Can I use 청결함 instead of 청결?

You can: 청결함이 유지돼요. It’s a bit more literary/descriptive. In formal/public wording, 청결이 유지되다 is the more common collocation.

What’s the nuance difference among 유지되다, 관리되다, and 지켜지다 here?

유지되다: a state/condition is maintained (neutral, common).
관리되다: is managed/maintained (hints at systematic management).
지켜지다: is kept/observed (often for rules/standards). Examples:
청결이 잘 유지돼요.
청결이 잘 관리돼요.
청결 기준이 잘 지켜져요.

Can I tweak nuance with particles like 도 or 만?

Yes:

도서관은 청결도 잘 유지돼요. = “Cleanliness, too, is well maintained.”
도서관은 청결만 잘 유지돼요. = “Only cleanliness is well maintained” (implies other aspects aren’t).

Any quick spacing tips for this sentence?

Write: 도서관은 청결이 잘 유지돼요.

Particles attach with no space (도서관은, 청결이).
잘 is separate.
유지돼요 is one word (verb + ending).