Learn Hardcore Korean: gagee gamyeon chaegeul sayo. - If I go to the store, I buy a book.

In Korean, subjects like I, you, or he/she are often dropped when they’re understood from context. Here, it’s a general statement (“if one goes to the store, one buys a book”) or a habitual action, so adding a pronoun isn’t necessary. If you want to be explicit, you could say 저는 가게에 가면 책을 사요 (As for me, if I go to the store, I buy a book).

What does -에 do in 가게에?

The particle -에 marks the destination or location goal. In 가게에 가면, it indicates to the store. It answers the question “where are you going?”

Why not use 가게에서?

-에서 marks where an action takes place (the location of doing something).

가게에서 책을 사요 means you buy a book at the store (action happens there).
Here, we’re describing going to the store, so we use -에 with 가다.

What is 가면 here?

가면 is 가다 (to go) plus the conditional suffix -면. It means if/when you go.
General rule for -(으)면:

If the verb stem ends in a vowel → add -면 (가 + 면 = 가면)
If it ends in a consonant → add -으면 (먹 + 으면 = 먹으면)

How does -면 differ from -서?

Both connect clauses, but they serve different roles:
• -면 expresses a condition or general rule → If/when X happens, Y follows.
• -서 expresses sequence or cause → Doing X, then Y happens.
So:
• 가게에 가면 책을 사요 = If/whenever you go to the store, you buy a book.
• 가게에 가서 책을 사요 = I go to the store and (then) buy a book.

Can 가게에 가면 책을 사요 be used for the future?

Yes. In Korean, the present tense form 사요 can cover future actions. If you want to emphasize “will buy,” use 사겠어요:
• 가게에 가면 책을 사겠어요 = If I go to the store, I will buy a book.

Why is 책을 used instead of 책이?

책을 uses the object marker -을 because 책 is the object of 사다 (to buy). The subject would take -이/가, but here 책 is what’s being bought, so it’s marked with -을.

Could I omit 가게에 and just say 가면 책을 사요?

You can, but it becomes vague: If/when you go (somewhere), you buy a book. Without specifying where, the sentence is incomplete in many contexts. It’s more natural to include 가게에 to show where.

Can I rearrange the word order to 책을 사요 가게에 가면?

No. Korean generally places adverbial or conditional clauses first, followed by the main clause. Swapping them breaks the natural flow and can confuse listeners.

What level of politeness is 사요?

사요 is the polite informal present tense (also called 합니다체). You’d use it in everyday conversation with strangers or acquaintances. For more formal situations, you’d say 삽니다. In casual speech with close friends, you might drop the ending and say 사.