가: 자야 씨, 왜 숙제 안 하셨어요?
Jaya, why didn’t you do your homework?
나: 오늘 숙제가 있었어요? 저는 숙제가 있는 줄 몰랐어요. 숙제가 없는 줄 알았어요.
Did we have homework for today? I didn’t know we had homework. I thought we didn’t have any.
가: 은혜 씨 남편 보셨어요? 정말 멋있던데요.
Did you see Eunhye’s husband? He’s really handsome.
나: 은혜 씨가 결혼을 했어요? 저는 은혜 씨가 결혼한 줄 몰랐어요. 결혼 안 한 줄 알았어요.
Did Eunhye get married? I didn’t know she got married. I was under the impression she wasn’t married.
The expression -(으)ㄴ/는/(으)ㄹ 줄 몰랐다 is used to end a clause stating something the speaker was not aware of or did not anticipate. -(으)ㄴ/는/(으)ㄹ 줄 알았다 on the other hand, is used to end a clause stating what the speaker had assumed to be the case; therefore, it expresses the speaker’s realization that his or her assumption was incorrect.
• 앤디 씨가 오늘 학교에 온 줄 알았어요. 학교에 오지 않은 줄 몰랐어요.
I thought Andy came to school today. i didn’t know he didn’t come.
• 바람이 많이 불어서 날씨가 추운 줄 알았어요. 그런데 밖에 나오니까 춥지 않아요.
The wind was blowing so hard I thought it was cold. But now that I am outside, it’s not cold.
• 저는 주영 씨가 중국 사람인 줄 몰랐어요. 한국 사람인 줄 알았어요.
I didn’t know Juyeong was Chinese. I thought she was Korean.
>> You can click on the title of each grammar below to learn the other grammar that also expresses ‘Conjecture and Supposition’:
01. -아/어 보이다
02. -(으)ㄴ/는 모양이다
03. -(으)ㄹ 텐데
04. -(으)ㄹ 테니까
05. -(으)ㄹ걸요
06. -(으)ㄴ/는/(으)ㄹ 줄 몰랐다[알았다]
07. -(으)ㄹ지도 모르다
>> Full of Intermediate grammar: Click here