Konnichiwa Mauricio-san!
"-moshi ka shite" and "-moshi ka shitara".
"moshi" express an assumption and means "if". "shite" is "suru" and means "do".
"-moshi ka shite" means perhaps, if, maybe, by any chance and etc...
And there are some declension of the ending, "-moshi ka shitara" and "-moshi ka suruto". Those difference express a difference of tense originally. "shite(shiteiru)" means the present tense. "shita" means the past tense. "suru" means the progressive form. But this tense is meaningless. Because the ending words don't means tense now.
An instance
Moshi ka suruto, Ashita ha Ame kamo shirenai.
Moshi ka shitara, Ashita ha Ame kamo shirenai.
Moshi ka shite, Ashita ha Ame kamo.
Those sentence means "Perhaps it'll rain tomorrow".
"naru hodo".
"naru hodo" means "I see", "sure", "It is true that...", "amply" and "asツ…as possible".
NANGI