Connective Ending 고 (and then)

At its core, 고 is a connective ending. You attach it to the end of a verb or an adjective stem to link it to another clause. It serves two main purposes. First, it lists things that are happening or qualities that exist together. For example, "The tea is hot AND the cake is sweet." Second, it shows a sequence of actions. For example, "I finish my homework AND THEN I play games." The best part? It doesn’t really care about the "subject" as much as other grammar points do. You can have one person doing two things, or two people doing different things. It’s flexible, like a yoga instructor for your sentences.

1. 1This is the part where you can breathe a sigh of relief. Unlike many Korean grammar rules, 고 is incredibly easy to form. You don't have to worry about whether the word ends in a vowel or a consonant (batchim).
2. 2Take the dictionary form of any verb or adjective (e.g., 먹다, 가다, 예쁘다).
3. 3Drop the 다 to find the stem (먹, 가, 예쁘).
4. 4Simply add 고 to the end of that stem.
5. 5That is it! 먹고, 가고, 예쁘고. It works the same for everything. Even the tricky irregulars usually behave themselves here. It’s basically a grammar vacation.

You will find yourself reaching for 고 in several real-world scenarios. Use it when you are describing someone’s appearance or personality. For example, "My brother is tall and kind." It’s perfect for listing your hobbies during a job interview or a first date. You can say, "I like reading and I like swimming." Another huge use case is daily routines. If you are telling a friend about your morning, you’ll use 고 to sequence your actions: "I wake up, wash my face, and eat breakfast." In a restaurant, it’s great for ordering: "I'll have the bibimbap and my friend will have the bulgogi." It keeps the conversation moving without awkward pauses.

While 고 is powerful, it isn't a magic wand for every "and" situation. Do not use it if there is a strong cause-and-effect relationship between two actions. If you want to say "I went to the park SO I met my friend," 고 won't work there. It also isn't used for "but" or "however." Most importantly, don't use it to connect two nouns directly. In English, we say "Apples and oranges." In Korean, you use 하고 or 이랑 for nouns. 고 is strictly for the "action" and "description" crowd. Think of it like a VIP club for verbs and adjectives only.

The most frequent trap students fall into is the "Tense Overload." In Korean, you usually don't need to put the past tense on the first verb when using 고. If the whole sentence is in the past, just conjugate the final verb. Saying 갔고 먹었어요 is like wearing two pairs of sunglasses—it’s redundant and looks a bit silly. Just say 가고 먹었어요. Another mistake is using 고 when the two actions are so tightly linked that the second one can't happen without the first. For those "glued together" actions, you’ll want to look at 아/어서 later. For now, keep 고 for things that are just happening in a row.

You might have heard of 아/어서, which also translates to "and" sometimes. Here is the secret: 고 is for a loose sequence or a list. It’s like saying "I did A, and by the way, I also did B." They are somewhat independent. 아/어서, on the other hand, implies a deeper connection, often where the first action provides the context or location for the second. If you use 고 for "I went to school and studied," it sounds like two separate events. If you use 아/어서, it sounds like you studied *at* the school you went to. Think of 고 as a chain and 아/어서 as glue.