The -고 있다 Form
Formation
The present progressive form -고 있다 attaches directly to the stem of an action verb. It's the most common way to say that someone "is doing" something.
먹다 → 먹 + 고 있다 → 먹고 있다
공부하다 → 공부하 + 고 있다 → 공부하고 있다
읽다 → 읽 + 고 있다 → 읽고 있다
Usage
Use -고 있다 to describe an action that is currently in progress. It's a versatile pattern used in both casual and formal speech.
Example: 지금 뭐 해요? (What are you doing now?)
→ 책을 읽고 있어요 . (I am reading a book.)
It can also describe a state that results from a completed action, which we will cover in a later section.
The -는 중이다 Form
The form -는 중이다 also expresses an ongoing action, but with a stronger emphasis on being "in the middle of" a process. It has two forms.
Formation 1: With Verbs
For action verbs, add -는 중이다 to the verb stem.
가다 → 가 + 는 중이다 → 가는 중이다
만들다 → 만들 + 는 중이다 → 만드는 중이다
Formation 2: With Nouns
You can also attach 중이다 directly to a noun (often a verb-derived noun). This is very common for activities.
회의 → 회의 중이다 (to be in a meeting)
식사 → 식사 중이다 (to be in the middle of a meal)
운전 → 운전 중이다 (to be in the middle of driving)
Key Differences
While -고 있다 and -는 중이다 can often be used interchangeably, they carry different nuances.
Feature · -고 있다 · -는 중이다
Meaning · General ongoing action. "is doing" · Emphasizes being "in the middle of" a process.
Example · 점심을 먹고 있어요.
(I'm eating lunch.) · 점심 식사하는 중이에요.
(I'm in the middle of eating lunch.)
Formality · Used in all situations. · Can feel slightly more formal or descriptive.