야구

In a sentence

• 저는 야구를 좋아합니다.

  I like baseball.

  In this sentence, '야구' is used as a noun referring to the sport of baseball, and '좋아합니다' indicates liking something.

• 야구 경기를 보러 갑시다.

  Let's go watch a baseball game.

  Here, '야구' is employed as a descriptor for '경기' (game), specifying the type of game being referenced.

• 어젯밤에 친구들과 야구를 했습니다.

  I played baseball with friends last night.

  In this sentence, '야구' again is used as a noun, but this time it is part of an activity being performed, i.e., playing baseball.