"Conosco loro sin da ieri."

Translation: I know them since yesterday.

[leonardicus]

"I know them since yesterday" is not idiomatic English. In English, this would be translated in past simple ("I knew them since yesterday.") or past perfect ("I have known them since yesterday.").

[ariannapeppa]

What the hell is this? It's so wrong!!!! It's Li conosco da ieri =)