Learn Hardcore Korean: gyohwaneun yeongeopsigan aneman ganeunghaeyo. - Exchanges are only possible during business hours.

은/는 marks a topic: “As for exchanges…” It often implies contrast or sets the frame for a rule or policy. Example nuance: “Exchanges (at least) are possible during business hours.”
이/가 marks a subject: 교환이 가능해요 feels more like a neutral statement of fact, “Exchange is possible.”
Both are grammatical. 교환은 sounds slightly more policy-like or contrastive; 교환이 sounds matter-of-fact.

Can I drop the particle and say 교환 영업시간 안에만 가능해요?

No. Korean normally needs a particle there. Use either 교환은 or 교환이 (or restructure to something like 영업시간 안에만 교환이 가능해요).

What exactly does 영업시간 mean? How is it different from 업무시간 or 근무시간?

영업시간: a store’s or service’s “business hours” (when they are open to customers).
업무시간: “office hours/working hours” for administrative work; often used by offices/agencies.
근무시간: employees’ “work hours/shift hours.”
In a retail or service context, 영업시간 is the natural choice.

Why 안에만? Could I say 영업시간에만, 영업시간 내에만, or 영업시간 동안만?

영업시간에만: very natural; “only during business hours.”
영업시간 안에만: acceptable; emphasizes “within the bounds of business hours.”
영업시간 내(에)만: more formal/official than 안에만; common on notices.
영업시간 동안만: “only for the duration of business hours,” highlighting the continuous span.
All work; pick based on tone. For signage/policy, 영업시간 내(에)만 or 영업시간에만 are most typical.

Can I use 안에서만 with time (e.g., 영업시간 안에서만 가능해요)?

Prefer not. 안에서 is spatial (“inside a place”). For time, use 에, 동안, 안/내(에). So say 영업시간에만, 영업시간 동안만, or 영업시간 내(에)만.

What happens if I move 만? For example, 교환만 영업시간에 가능해요.

영업시간(안에)만: restriction on time → “only during business hours.”
교환만 영업시간에 가능해요: restriction on service → “only exchanges are possible (during business hours),” implying refunds/returns aren’t.
교환은 영업시간에만 vs 교환만 영업시간에 change focus. Place 만 right after what you are limiting.

Why use 가능해요 instead of 할 수 있어요 or 돼요?

가능하다: “to be possible,” formal/impersonal; common in policies: 교환이 가능해요/가능합니다.
할 수 있다: “can do”; more personal-ability feel. 교환할 수 있어요 is fine but sounds less policy-like.
되다: “to be allowed/okay”; very common in spoken rules: 교환은 영업시간에만 돼요.
So: signage → 가능합니다; casual rule → 돼요; personal ability → 할 수 있어요.

Is 가능하세요 or 가능하십니다 correct/polite here?

Not in this meaning. 가능하다 describes the situation, not the person. Use impersonal forms:

Polite: 가능해요
Formal: 가능합니다 When asking a person if they’re available, you might say 가능하세요? (“Are you available?”), but that’s a different context.

Can I change the word order, like 영업시간 안에만 교환이 가능해요?

Yes. Common alternatives:

영업시간 안에만 교환이 가능해요.
영업시간 안에만 교환은 가능해요. Fronting the time phrase is natural. On signs you’ll also see clipped noun-phrase styles: 영업시간 내 교환 가능.

How do I say this more formally for a sign?

교환은 영업시간 내에만 가능합니다.
Even tighter: 영업시간 내 교환 가능
For a stronger prohibition outside hours: 영업시간 외 교환 불가.

How do I express the opposite (not possible outside business hours)?

What’s the difference between 교환, 환불, and 반품?

교환: exchange (swap for another item).
환불: refund (get your money back).
반품: return (send/bring the item back; may lead to a refund).
Policies often list them separately because the rules differ.

What part of speech is 교환 here? How is it different from 교환하다?

교환 is a noun (“exchange”). The sentence uses a light predicate: 교환(이) 가능하다 (“exchange is possible”).
교환하다 is the verb (“to exchange”): e.g., 영업시간에만 교환할 수 있어요 or 영업시간에만 교환해 드려요.

Any pronunciation tips for this sentence?

영업시간 undergoes tensification: pronounced roughly [영업씨간], romanized “yeongeop-ssigan.”
교환은: “gyo-hwa-neun” (교환 has a glide; don’t split as “go-han”).
가능해요: “ga-neung-hae-yo.”
Linking and tensification make fluent speech sound tighter than the spelling.

Is there any spelling/spacing I should watch for (e.g., 되요 vs 돼요, 영업 시간)?

If you use 되다: the polite form is 돼요, not “되요.”
영업시간 vs 영업 시간: both are seen; the closed form 영업시간 is common because it’s a set term. Be consistent within a document.
Particles attach without a space: 교환은, 안에만.

Could I say the same thing more casually?

Yes:

교환은 영업시간에만 돼요.
Or shorten the time phrase: 영업시간에만 교환돼요.
These sound friendlier/colloquial than 가능해요.