Core Pattern Rule: -고 나서 (After doing)
This pattern connects two actions, indicating that the second action takes place only after the first one is completely finished. It's equivalent to saying "after doing (something)..." in English.
Meaning & Usage
Meaning: It marks a clear sequential order of events. The action in the first clause must be fully concluded before the action in the second clause can begin.
When to use: Use it to remove any ambiguity about the order of actions. For example, when giving instructions or describing a series of steps you took or will take.
Formation
Simply attach -고 나서 to the stem of any verb, regardless of whether it ends in a vowel or a consonant.
먹다 (to eat): 먹 + 고 나서 → 먹고 나서
씻다 (to wash): 씻 + 고 나서 → 씻고 나서
졸업하다 (to graduate): 졸업하 + 고 나서 → 졸업하고 나서
먹고 나서 후회했어. / 졸업하고 나서 취직했어요. / 씻고 나서 잘 거야.
Synonyms & Differences: -고 vs. -고 나서
Learners often wonder about the difference between -고 and -고 나서. While they can sometimes be used interchangeably, they have distinct nuances.
-고 나서 (Strictly Sequential)
This pattern strongly emphasizes that the first action is 100% complete before the second one starts. It focuses on the temporal sequence. 나서 comes from the verb 나다 (to arise/emerge), so it literally means "after the first action arises and is done..."
Best for: 숙제하고 나서 놀아. (Play after you finish your homework.) The sequence is the main point.
-고 (More Versatile)
-고 can mean "and then" (sequence), but it can also simply link two related actions or states without a strong emphasis on completion. It can be ambiguous.
Sequential: 밥 먹고 약 먹었어요. (I ate and then took medicine.) - Here it works like -고 나서.
Listing: 저는 노래하고 춤췄어요. (I sang and danced.) - The actions are just listed, not necessarily in a strict order. Using -고 나서 here would be unnatural.
Tip: When in doubt, use -고 나서 to make the sequential relationship crystal clear. You can often drop 나서 in casual speech if the context is obvious, but keeping it is never wrong when you mean "after."