-는 줄 알다/모르다

그가 선생님인 줄 몰랐어요.

I didn't know he was a teacher.

오늘 시험이 있는 줄 몰랐어요.

I didn't know there was an exam today.

비가 오는 줄 알았어요.

I thought it was raining.

그렇게 어려운 줄 몰랐어요.

I didn't know it was that difficult.

한국어를 할 줄 아는 줄 몰랐어요.

I didn't know you could speak Korean.