Hi Cherry*
I am George - a fellow student here at KC101. Nice to meet you.
I will get this ball rolling (so to speak) by contributing some input that will no doubt confuse you even further, but don't worry the native Koreans will come along after me with a more complete explanation.
First off:
12월
에 와요 - (He/She/They) come
in December --the particle "에" is a 'post position' that is the equivalent "at" or "in" or "during" (and "to") --so I don't think you would use the object particle 을/를 after 12월
와요 = 옵니다 = come/comes
오고 있습니다 = is coming (now), is on the way
올 거에요 (것이다/겁니다) = will come, will arrive
Now for the really confusing part:
Coming vs Going (Going to, will go to) and the Korean mindset -- in the above cases Koreans are typically talking about someone else coming/arriving to a location they currently occupy, but there are a few exceptions, one might be "I'll come(be) back again (to the place I am now in/at)" (나는) 다시 올거에요.
Ok so how do you say 'I'm coming in December?" I think "I'm
going (to Korea) in December." 12월에 가요 is correct, "I will go to Korea in December" "나는 12월에 한국으로 갈 거에요" because you are leaving the place you ARE and GOING to the place you will arrive at.
The word for "arrive" is
도착하다 - so if you wanted to say 'I am going to arrive December 1st" you could say something like 12월 1일에 도착할 거에요. "I will arrive in Korea on December 15, at 2:00PM."(난는) 12월 15일 2시에 한국에 도착할 거에요.
I THINK I'm coming in December.
In this example "I THINK" expresses the idea of uncertainty or doubt, kind of 'planing' so it would be more accurate to translate the phrase using 'maybe/perhaps' or 'there is a chance:'
Perhaps I will go (come) to Korea in December - 아마 12월에 한국으로 갈 거에요.
There is a chance I will go to Korea in December - 12월에 한국으로 갈 가능성이 있어요.
I am planning to go to Korea in December - 12월에 한국으로 갈 계획 있어요.
Lit: I have a thought to go to Korea in December - 12월에 한국으로 갈 생각 있어요
"I think" or "thinking of" this English expression can be translated into Korean in a number of different ways; the meaning sometimes is implied by using future tense (as was the case of your example), and sometimes other (more accurate) vocabulary e.g. 'planning' or 'considering' is used. Of course 'thinking of' can be translated exactly as it is, but in the case of "I'm thinking of going to Korea" if we translated that sentence literally word-for-word it would creates a somewhat awkward expression.
Ok now we sit back and wait for clarification from Tim, Sean, and maybe Julia (if we are really lucky)..
Keep up the great efforts!
George
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