Learn Korean: State Verb + 는지

Let’s take a look at the Korean sentence pattern State Verb + 는지. With this pattern, we can make the following English sentences: I know why he is happy, I know what is important, and I know why she is lonely. The sentences include the WH-words and state verbs (happy, kind, and lonely). Unlike when the verb is an active verb, this one is limited to why, who, and what. It is given that the subject is mentioned at the beginning of the sentence so we are going to pay attention to the clauses. The WH-words come first before the verb. The verb is conjugated accordingly. In present tense, we attach ㄴ to verb stems that end in a vowel and 은 to verb stems that end in a consonant. For example, 중요하다 (to be important) becomes 중요한지 and 좋다 (to be good) becomes 좋은지. In past tense, we conjugate the verb to their 았/었/였 form first before adding 는지. Take note, it's 는지 and not (으)ㄴ지. So 중요하다 becomes 중요했는지 and 좋다 becomes 좋았는지. Now we can form the clauses why (he) is happy and what is important. We say 왜 기분이 좋은지 and 뭐가 중요한지 respectively. To complete the sentences, we use either 알다 (to know) or 모르다 (to not know). They are conjugated into 알아요 and 몰라요 in polite speech.

걔가 왜 기분이 좋은지 알아.

I know why he is happy.

뭐가 중요한지 알아.

I know what is important.

걔가 왜 슬픈지 알아.

I know why she is lonely.