Learn Hardcore Korean: muneul yeolgo nagayo. - I open the door and go outside.

The -고 ending is a verb connective that links two actions sequentially, similar to “and” or “then” in English. In 문을 열고 나가요, it means “open the door and then go out.” Both verbs share the same subject when you use -고.

How is 열고 different from 열어서?

Both -고 and -어서 link actions, but there’s a subtle nuance:
• -고 simply lists actions in order: “A and then B.”
• -어서 often implies a cause-and-effect or that one action leads more directly into the next.
In casual speech, 열고 나가요 is more common for a simple sequence, while 열어서 나가요 can sound a bit more “because I opened it, I went out.”

Why is 문 followed by 을?

을 is the object particle for nouns ending in a consonant. Here, 문 (“door”) is the direct object of 열다 (“to open”). So 문을 열다 literally means “to open the door.”

Why is there no subject in 문을 열고 나가요?

Korean frequently omits the subject when it’s clear from context. If you’re talking about your own actions, you don’t need to say 저는 (“I”). The listener infers who is doing the opening and leaving.

What does the -요 ending in 나가요 indicate?

The -요 ending marks polite informal speech, often called the 요-form. It’s friendly yet respectful, suitable for strangers or people you don’t know very well.

Can I say 나가 instead of 나가요?

Yes. 나가 (plain form) is used among close friends, family, or when writing, but it’s less polite. To maintain politeness with most people, use 나가요.

What’s the difference between 나가다 and 나오다?

Both mean “to go out,” but from different points of view:
• 나가다: speaker is inside, describing going from the inside to the outside.
• 나오다: speaker is outside or at a neutral point, describing something/someone coming out toward them.

Could I add 밖으로 and say 문을 열고 밖으로 나가요?

Yes, you can. 밖으로 (“to/into the outside”) adds emphasis on direction, but it’s usually redundant since 나가다 already implies going outside. The shorter version is more natural.

What about using -고 나서 as in 문을 열고 나서 나가요?

-고 나서 also links actions, with a bit more emphasis on “after doing A.” So 열고 나서 나가요 sounds like “after opening the door, I go out.” It’s slightly more formal or explicit about the sequence than plain -고.