si tard
If I had come later, you would have said "Why so late?"
Si j’étais arrivé plus tard, tu aurais dit : « Pourquoi si tard ? »
— The Asthenic Syndrome (1989)
Why did you come home so late?
Pourquoi es-tu rentré si tard ?
We've only been married for a week and you're already coming home so late!
Ça ne fait qu’une semaine qu’on est mariés et tu rentres déjà si tard !