발생하다([bal-saeng-ha-da/occur]) means something happens. In polite speech, say 발생해요([bal-saeng-hae-yo]).
발생했어요([bal-saeng-hae-sseo-yo/occurred]) is the polite past form. Example: 발생했어요 (It occurred).
발생해야 해요([bal-saeng-hae-ya hae-yo/have to occur]) means it must occur. Example: 발생해야 해요 (It has to occur).
발생하다([bal-saeng-ha-da/occur]) means "to occur". Often used for accidents, problems, errors.
1. Daily: “무슨 일이 발생해요? (mu-seun i-ri bal-saeng-hae-yo)” What occurs?
2. Past: 발생했어요([bal-saeng-hae-sseo-yo/occurred]) occurred.
3. Duty: 발생해야 해요([bal-saeng-hae-ya hae-yo/have to occur]) has to occur.
4. Warning: 발생하지 마세요([bal-saeng-ha-ji ma-se-yo/don't occur]) don't occur.
A: What occurs?
B: 사고가 발생해요. B: sa-go-ga bal-saeng-hae-yo.B: An accident occurs.
A: 어디서 발생해요? A: eo-di-seo bal-saeng-hae-yo?A: Where does it occur?
B: 공장에서 발생해요. B: gong-jang-e-seo bal-saeng-hae-yo.B: It occurs at the factory. - 발생하다([bal-saeng-ha-da/occur])
A: When did it occur?
B: 어제 발생했어요. B: eo-je bal-saeng-hae-sseo-yo.B: It occurred yesterday.
A: 어디서 발생했어요? A: eo-di-seo bal-saeng-hae-sseo-yo?A: Where did it occur?
B: 회사에서 발생했어요. B: hoe-sa-e-seo bal-saeng-hae-sseo-yo.B: It occurred at the company. - 발생했어요([bal-saeng-hae-sseo-yo/occurred])
A: When does it have to occur?
B: 오늘 발생해야 해요. B: o-neul bal-saeng-hae-ya hae-yo.B: It has to occur today.
A: 어디서 발생해야 해요? A: eo-di-seo bal-saeng-hae-ya hae-yo?A: Where does it have to occur?
B: 공장에서 발생해야 해요. B: gong-jang-e-seo bal-saeng-hae-ya hae-yo.B: It has to occur at the factory. - 발생해야 해요([bal-saeng-hae-ya hae-yo/have to occur])
• 발생하다([bal-saeng-ha-da/occur]) occur
- 발생했어요([bal-saeng-hae-sseo-yo/occurred]) occurred
- 발생하고 싶어요([bal-saeng-ha-go si-peo-yo/want to occur]) want to occur
- 발생해야 해요([bal-saeng-hae-ya hae-yo/have to occur]) have to occur
- 발생하지 마세요([bal-saeng-ha-ji ma-se-yo/don't occur]) don't occur