어제부터

In a sentence

• 어제부터 비가 내리고 있습니다.

  Since yesterday, it has been raining.

  Here, '어제부터' (since yesterday) marks the starting time of a continuous action—raining—indicating it began yesterday and is still continuing.

• 어제부터 새로운 책을 읽기 시작했어요.

  Since yesterday, I started reading a new book.

  In this sentence, '어제부터' introduces the point in time when a new ongoing action—reading a book—was initiated.

• 어제부터 나는 기분이 조금 이상해요.

  Since yesterday, I have been feeling a little strange.

  Here, '어제부터' outlines the beginning of a subjective state—feeling strange—that started yesterday and persists to the present.