Rob: Is that rain? Wasn’t it nice and sunny this morning?

Ms. Brown: Well, you must have missed the weather report this morning. The forecaster said scattered thunderstorms.

Rob: I’ve just been too busy to watch the news or read the paper. You wouldn’t have an extra umbrella I could borrow, would you?

Ms. Brown: It just so happens that I do. This is an umbrella I forgot at the office a few weeks ago.

 It just so happens that I do. 에서 so의 품사와 의미를 알 수 있을꺄요?

또한 이 문장에서 so의 위치를 동사다음으로 보내고 

 It just happens so. 로 끝내도 제 생각에는 전혀 이상없지 않나 싶네요 ? 아닌가요? (제 생각에는 so는 부사로 동사를 수식하며 강조의 의미로 동사앞에 위치)