-고 있다
RuleVerb stem + -go itda: marks an action in progress ("be V-ing") or a continuing state of wearing/holding.
Curiosity
How does "I eat" differ from "I am eating"? How do you form the English "-ing" in Korean?
Intuition
-go itda holds a verb "in progress now." Attach -go to the stem, then add itda ("to exist"): the action is ongoing and present. With verbs like ipda (wear) or sseuda (put on), it also means a lasting state (ipgo itda, "be wearing").
Visualization
gada (dictionary) → ga (stem) → gago itda. -go itda attaches to the stem.
가다gadadictionary form
Essence
Verb stem + -go itda (gago isseoyo, meokgo itseumnida). It marks progress; the honorific is -go gyesida (the grandfather is sleeping). With ipda, deulda, sseuda it gives a resulting continuing state (an-gyeong-eul sseugo itda, "be wearing glasses"). It is not used with adjectives.
Examples
지금 밥을 먹고 있어요.
I am eating now.
동생은 음악을 듣고 있어요.
My younger sibling is listening to music.
그는 안경을 쓰고 있어요.
He is wearing glasses.
Mini-quiz
"I ___ a book now." (progressive "am reading") Which fits?