Chyba wiem, gdzie jest Tom.

[AlexG71]

• chyba adv = probably, maybe, perhaps.
  ~ nie = probably not, I don’t think so.
  ~ tak = probably so, I suppose so.
  ~ , że = unless

[Jankraus92]

Interesting fact is that “chyba” in Czech means “mistake”, but in Polish it means “probably”.