열다([yeol-da/open]) is the basic verb for opening. In polite speech, say 열어요([yeo-reo-yo]).
열었어요([yeo-reo-sseo-yo/opened]) is the polite past form of 열다. Example: 문을 열었어요 (I opened the door).
열어야 해요([yeo-reo-ya hae-yo/have to open]) means you must open something. Example: 가게를 열어야 해요 (I have to open the store).
열다([yeol-da/open]) means "to open". It is the basic verb for opening a door or window.
1. Place: “문 열어요? (mun yeo-reo-yo?)”
2. Past: 열었어요([yeo-reo-sseo-yo/opened]) opened.
3. Duty: 열어야 해요([yeo-reo-ya hae-yo/have to open]) have to open.
4. Warning: 열지 마세요([yeol-ji ma-se-yo/don't open]) don't open.
A: Do you open the door?
B: 네, 문을 열어요. B: ne, mu-neul yeo-reo-yo.B: Yes, I open the door.
A: 언제 열어요? A: eon-je yeo-reo-yo?A: When do you open it?
B: 아침에 열어요. B: a-chi-me yeo-reo-yo.B: I open it in the morning. - 열다([yeol-da/open])
A: Did you open the door yesterday?
B: 네, 아침에 열었어요. B: ne, a-chi-me yeo-reo-sseo-yo.B: Yes, I opened it in the morning.
A: 창문도 열었어요? A: chang-mun-do yeo-reo-sseo-yo?A: Did you also open the window?
B: 네, 창문도 열었어요. B: ne, chang-mun-do yeo-reo-sseo-yo.B: Yes, I also opened the window. - 열었어요([yeo-reo-sseo-yo/opened])
A: Do you have to open it now?
B: 네, 가게를 열어야 해요. B: ne, ga-ge-reul yeo-reo-ya hae-yo.B: Yes, I have to open the store.
A: 몇 시에 열어야 해요? A: myeot si-e yeo-reo-ya hae-yo?A: What time do you have to open it?
B: 9시에 열어야 해요. B: 9-si-e yeo-reo-ya hae-yo.B: I have to open it at 9 o'clock. - 열어야 해요([yeo-reo-ya hae-yo/have to open])
• 열다([yeol-da/open]) open
- 열었어요([yeo-reo-sseo-yo/opened]) opened
- 열고 싶어요([yeol-go si-peo-yo/want to open]) want to open
- 열어야 해요([yeo-reo-ya hae-yo/have to open]) have to open
- 열지 마세요([yeol-ji ma-se-yo/don't open]) don't open