since when?
成語所屬單字since
since when? — 慣用語
1. used to express surprise or disagreement that something is true, often suggestin
1.慣用語
釋義
從什麼時候開始？（表示驚訝或不滿）
used to express surprise or disagreement that something is true, often suggesting the speaker believes the opposite is the case
例句
Yael claimed she had never borrowed my books. Since when? I saw them on her desk last week.
Since when does the library charge for study rooms? That was never the rule before.