Commonly confused Korean grammar

40 pairs of grammar points that learners often mix up, with the key difference, rules of thumb and example sentences.

Beginner · TOPIK I (22)

은/는 vs 이/가은/는 marks the topic — what the sentence is about, often known information or something being contrasted — while 이/가 marks the grammatical subject and puts the focus on new information, i.e. exactly who or what.
에 vs 에서에 marks a destination, the place where something exists, or a point in time; 에서 marks the place where an action happens, or a starting point ('from').
에 vs 에게, 한테, 께Both can mean 'to' a recipient, but 에 is for things, places and organisations, while 에게/한테/께 are for people and animals.
에 vs (으)로With movement verbs, 에 focuses on the destination point, while (으)로 focuses on the direction ('towards'). (으)로 also marks means, tools and change; 에 also marks location of existence and time.
만 vs 밖에Both mean 'only', but 만 is neutral and works in any sentence, while 밖에 must be followed by a negative predicate and stresses 'nothing but… (and that's not much)'.
-아요/어요 vs -ㅂ니다/습니다Both are polite endings. -아요/어요 is the soft, everyday polite style; -ㅂ니다/습니다 is the formal style used in presentations, news, business and the military.
-고 vs -아서/어서When linking actions in sequence, -아서/어서 is used when the first action sets up the second (go somewhere and do something there, make something and use it), while -고 simply lists 'A, and then B'.
-아서/어서 vs -(으)니까Both give a reason, but -아서/어서 states a cause in a neutral, natural way, while -(으)니까 presents the speaker's own reasoning and can be followed by commands and suggestions.
-(으)니까 vs -기 때문에Both give reasons. -(으)니까 is conversational and subjective and can take commands/suggestions; -기 때문에 is objective, emphasises the cause, and is common in writing and formal speech, but does not go with commands or suggestions.
-지만 vs -(으)ㄴ데/는데-지만 is a clear 'but'; -(으)ㄴ데/는데 is broader — it can mark a soft contrast, but very often it just sets the scene or gives background before the main point.
-지 않다 vs -지 못하다-지 않다 (안) is plain negation or 'not doing' by choice; -지 못하다 (못) means 'cannot' — inability or outside circumstances stop you.
-(으)ㄹ게요 vs -(으)ㄹ래요-(으)ㄹ게요 is a promise or a heads-up to the listener ('I'll do it', with the listener in mind); -(으)ㄹ래요 expresses your own wish or preference ('I want to / I'll have…') and is also used to ask what the listener wants.
-(으)ㄹ까요? vs -(으)ㄹ래요-(으)ㄹ까요? asks for the listener's opinion ('Shall we…?', 'Shall I…?') or wonders ('Do you think…?'); -(으)ㄹ래요? asks about the listener's own wish ('Do you want to…?') and, as a statement, gives your own wish.
-(으)ㄹ 거예요 vs -(으)ㄹ게요-(으)ㄹ 거예요 states a plan or a prediction neutrally, without involving the listener; -(으)ㄹ게요 is a promise or decision made for or in response to the listener.
-(으)러 vs -(으)려고Both mean 'in order to'. -(으)러 only works when the main verb is a movement verb (가다, 오다, 다니다); -(으)려고 works with any verb but cannot be followed by a command or suggestion.
-네요 vs -군요/는군요Both express surprise at something newly learned. -네요 leans toward direct, in-the-moment perception and is very conversational; -군요 leans toward 'Ah, I see' realisation, often through inference or what someone has just told you.
-(으)면 vs -(으)ㄹ 때-(으)면 is a condition or assumption ('if / whenever'); -(으)ㄹ 때 refers to the time or period when something happens ('when / at the time').
-아도/어도 되다 vs -(으)면 되다-아도/어도 되다 gives permission ('it's OK to…'); -(으)면 되다 states a sufficient condition ('you just need to…, and that's it').
-(으)ㄹ 수 있다/없다 vs -(으)ㄹ 줄 알다/모르다-(으)ㄹ 수 있다/없다 covers ability in general, including whether circumstances allow it; -(으)ㄹ 줄 알다/모르다 is only about knowing how to do something — a learned skill.
-게 되다 vs -아/어지다-게 되다 means 'come to / end up (doing)' because of circumstances, mostly with verbs; -아/어지다 on adjectives means 'become' (a gradual change of state), and on verbs it usually makes a passive.
-고 싶다 vs -(으)면 좋겠다-고 싶다 is a direct desire to do something yourself; -(으)면 좋겠다 is a wish that a situation would come about — it can involve other people or things beyond your control.
(이)나 vs -거나Both mean 'or', but (이)나 attaches to nouns while -거나 attaches to verb and adjective stems. (이)나 also means 'just… (for lack of better)' and 'as many as'.

Intermediate · TOPIK II (18)