Hey Mohammad —
I think that (converting one phrase for another) is a tool that you can keep in your arsenal, and it can certainly prove to be extremely useful when you feel lost or stuck, but ideally I would use it as a secondary method — in general, you want to first do your best to try and understand conditional statements correctly in the manner in which the statements are given — if a statement is causing you trouble to begin with, I think there are increased chances that you may accidentally change the meaning by altering it — hth — mk