* Form : verb stem + -기 ex) 하|다 (to do) --> 하 + 기 --> 하기 (doing) 먹|다 (to eat) --> 먹 + 기 --> 먹기 (eating) 놀|다 (to play) --> 놀 + 기 --> 놀기 (playing) As you might notice, when you add -기 to the verb stem, it changes verbs to nouns. So it is like gerund in English. * 내(my) 취미는 (hobby) 야구하기예요. (is playing baseball) * More sample sentences e.g. 한국어 배우기가 어렵지 않아요. (Learning Korean is not difficult.) e.g. 제 새해 결심은 '운동 열심히 하기'예요. (My new year's resolution is exercising hard.) Hope it helps!

my hubby is playing baseball