"평창에서 동계 올림픽을 개최합니다."
Translation:They host the Winter Olympics in Pyeongchang.
without a subject or a context, theres no way of identifying the subject of this sentence!
"동" in 동계 stands for winter in this case. The Chinese character equivalent (Hanja) is "冬".
Makes it sound as if it's permanently hosted there. I would go for present continuous or future tense personally