This is the 244th most frequent Korean word.
시작했다
"Started" or "began."
In this sentence, '시작했다' is used to denote the commencement of a specific activity or endeavor, in this case, starting a new job.
그는 새로운 일을 시작했다.
He started a new job.
Here, '시작했다' is utilized to indicate the beginning of a natural event, referring to the start of rainfall.
비가 오늘 아침부터 시작했다.
The rain started this morning.
In this context, '시작했다' implies the restarting or resumption of an activity that was previously paused, in this case, studying.