화나다 - 화내다 You are angry. - You express out your angerness. 끝나다 - 끝내다 The event(whatever it is) came to an end. - You ended the event. 나타나다 - 나타내다 Sth was shown. - You showed sth. 지나다 - 지내다 pass - live along

A verb ending in 나다 is passive and a verb ending in 내다 is active. For example: 끝내다 = to finish 끝나다 = to be finished 나다 and 내다 can actually be used as standalone verbs as well as be attached to other words. Both of their meanings are very complex and depend heavily on the situation, but their general meanings are: 나다 = for something to come up/arise/occur 내다 = to make something come up/arise/occur However, not all words ending in 나다 have an equivalent 내다 verb (and vice-versa). To find out more on korean passive verbs you can check this: http://www.howtostudykorean.com/unit1/unit-1-lessons-9-16/lesson-14-korean-passive-verbs