First listen to this lesson: -(으)ㄴ/는지 http://www.talktomeinkorean.com/lessons/level-5-lesson-18/ Then listen this lesson: -지요/-죠 http://www.talktomeinkorean.com/lessons/level-4-lesson-4/ Read the PDF as well.

는(present tence)/은,ㄴ(past tence) is used for verb. 은,ㄴ(present tence)is use for adjective. there is no past tence for adjective. e.x. 불고기를 먹는 지(if (somebody) eat bulgogi or not) , 불고기를 먹은 지 (if (somebody) ate bulgogi or not).

the independent 지 at the ending means "confirmation", similar to "~~~. right?" e.x. A: 에제 들어왔지?(you came back yeasterday, right?)