Well, let's first look at the probability -- and this is very, very difficult to estimate -- but there have been only four studies on this in recent years, which is surprising.
먼저 확률을 살펴 봅시다 이것은 가늠하기 아주 어려운 문제지요 그렇지만 최근 몇 년간 단지 4개의 연구가 진행되었으며, 놀라운 것입니다