G15.3 ~(으)면

~(으)면 [~으면 after a consonant and ~면 after a vowel] expresses a condition under which a main event takes place.

Note: ~(으)면 in Korean is not the same as 'if' in Eglish. 'If' in English only refers to a hypothetical event, whereas ~(으)면may refer to an event that may actually take place as well as a hypothetical event.

~(으)면 can be translated into English in two ways:
  (i) Hypothetical condition:  If ~
  (ii) Non-hypothetical condition: When ~

(i) Non-hypothetical:
    요즘 날씨가 더워요.
    그렇지만, 가을이 되면 (When fall comes/(x)If fall comes) 날씨가  시원할 거예요.
    [Fall is actually coming]

     학기가 끝나면 (When/(x)If the semester is over)/ 방학하면 뭐 할  거예요?


    

     A: 이번 주말에 뭐 할 거예요?
     B: 친구가 놀러 올 거예요.
     A: 친구가 오면 (When/(x)If your friend comes) 친구하고 뭐 할 거예요?
     B: 시카고에 갈 거예요.

(ii) Hypothetical:
     A: 돈 많아요?
     B: 아니오.
     A: 돈이 많으면 (If/*When you have a lot of money) 뭘 하고 싶어요?
     B: _____________________________________

    

한국어를 잘 하고 싶으세요?
     한국어를 잘 하고 싶으면 (If/(x)When you want to speak Korean well) ___________________.

    시간 있으면 숙제 좀 도와 주실래요?
    질문 있으면 연구실에 와서 물어 보세요.

     A: 이번 주말에 뭐 할 거예요?
     B: 친구가 오면 (If/(x)When a friend of mine comes) 같이 영화보러 가고,
         친구가 안 오면 (If/(x)When a friend of mine doesn't come) 집에서 야구 볼 거예요.
 

 

~(으)면 vs. ~(으)ㄹ 때
 Both (으)면 and ~(으)ㄹ 때 can be translated into �when ~� in English. But the two constructions have different communicative functions:

~(으)면: when the designated situation indeed occurs
  이번 학기가 끝나면/(x)끝날 때 한국에 갈 거예요.
  When this semester is over, I am going to Korea.


 한국에 가면/(x)갔을 때 친구들을 [friends in Korea when I get to Korea] 많이 만날 거예요.
 cf. 한국에 갈 때 친구들을 [friends in the states before I go] 많이 만날 거예요.

~(으)ㄹ 때: at the time of . . .
한국에 갔을 때 친구들을 많이 만났어요.

 ~(으)면 sets up a condition under which an event is realized, whereas ~(으)ㄹ 때 sets up a time reference with respect to which another event can be defined.

  ~(으)ㄹ 때 usually refers to a real situation (it does not make much sense to set up as a reference event an event that does not take place), whereas ~(으)면 usually refers to an event whose reality does not matter. With ~(으)면, your focus of attention is that an event is realized when this condition designated by ~(으)면 is met. Therefore, there is a contingent relation between the two events. The realization of the second event is relevant only when the first conditional event is realized. With ~(으)ㄹ 때, the two events do not have any relation, except that one event is described with respect to the time point at which the first event takes place. There might be a situation when both constructions are allowed, though: