On this page: "Tenses", it says that the past perfect continuous conditional can be used to talk about the future, but does not give an option for the past perfect simple conditional: "If I had been working tomorrow, I could not have agreed." - why could one not also say: "If I had worked tomorrow, I could not have agreed." using the third conditional: "Third Conditional" - is only the continuous form of the past perfect conditional therefore grammatically correct to use to talk in a future sense?

Thank you.

Philip.