Asking About the Past

해요 [hae-yo] I do → 했어요 [hae-sseo-yo] I did

How to change Korean verb from present tense to past tense.

Step 1: Drop the 요 [yo]. 해요 [hae-yo] → 해 [hae]

Step 2: Add -ㅆ어요 [sseo-yo]. 해 [hae] → 했어요 [hae-sseo-yo]

숙제했어요 [suk-je-hae-sseo-yo]
I did my homework.

• 숙제해요 [suk-je-hae-yo] I do my homework. → 숙제했어요 [suk-je-hae-sseo-yo]

어제 아침을 먹었어요 [eo-je a-chim-eul meo-geo-sseo-yo]
I ate breakfast yesterday.

• 어제 [eo-je] means "yesterday"
• 아침 [a-chim] means "breakfast"
• Step 1: 먹어요 [meo-geo-yo] I eat → 먹어 [meo-geo]
• Step 2: 먹어 [meo-geo] → 먹었어요 [meo-geo-sseo-yo] I ate

뭐했어요? [mwo-hae-sseo-yo?]
What did you do?

• 뭐해요? [mwo-hae-yo?] What do you do? → 뭐했어요? [mwo-hae-sseo-yo?] What did you do?

주말에 공원에서 영화를 봤어요. [ju-ma-re gong-won-e-seo yeong-hwa-reul bwa-sseo-yo]
I watched a movie in the park during the weekend.

• 주말 [ju-mal] means "weekend"
• 에 [e] particle that means "during"
• 공원 [gong-won] means "park"
• 에서 [e-seo] particle that means "at"
• 영화 [yeong-hwa] means "movie"
• 를 [reul] particle that marks the subject
• 봤어요 [bwa-sseo-yo] means "I watched"

• A: 어제 뭐했어요? [eo-je mwo-hae-sseo-yo?]
  What did you do yesterday?
• B: 어제 도서관에서 공부했어요.
  I studied at the library yesterday.
• B: 음..지난주에 뭐했어요?
  Hmm.. What did you do last week?
• A: 지난주에 영화를 봤어요. [ji-nan-ju-e yeong-hwa-reul bwa-sseo-yo]
  I watched a movie last week.
• B: 어디에서 영화를 봤어요?
  Where did you watch the movie?
• A: 영화관에서 영화를 봤어요. [yeong-hwa-gwan-e-seo yeong-hwa-reul bwa-sseo-yo]
  I watched the movie at the movie theater.
• B: 아하
  I see.