I am noticing some sentences uses "se" while others use "ĉu". I have previously been confused about what sentences use which, and this thread has not helped with my confusion. Can either word be used in the above sentences, or is one word better than the other?

Se pluvos sabate, ni ne iros. Sed mi ne scias, ĉu pluvos sabate, do eble ni iros, eble ne.

"se" is used for if/then statements - that is, for conditional situations. IF...something, THEN... something else [the "then" is not always explicitly stated - could be "If you take my couch, will you pay me?"]

Confusingly, English (and some other languages like French) use "if" (or "si" in French) for situations that aren't conditional. They're situations where we often use "whether" in English.

I don't know whether he will come
I don't know if he will come

= Mi ne scias ĉu li venos.

There is no if/then here; "if" he comes, there is no expected result, so this isn't a situation where we should use "se".

English and French like to use a form of "if" in this case, but "se" isn't an option in Esperanto.

Bottom line - if you feel like using "if" somewhere in English, and it isn't an if/then type situation, and if it would still make sense grammatically if you were to substitute "whether" for "if" - then you should use "ĉu".

If substituting "whether" for "if" makes no sense whatsoever, then it probably is a conditional type situation, and you probably do want "se" in Esperanto.

erinja:Bottom line - if you feel like using "if" somewhere in English, and it isn't an if/then type situation, and if it would still make sense grammatically if you were to substitute "whether" for "if" - then you should use "ĉu".
…

If substituting "whether" for "if" makes no sense whatsoever, then it probably is a conditional type situation, and you probably do want "se" in Esperanto.

How does one say, "Holy cats!" in Esperanto? I am deeply appreciative of what I am learning here. Thank you!

sudanglo:Se pluvos sabate, ni ne iros. Sed mi ne scias, ĉu pluvos sabate, do eble ni iros, eble ne.

That clears up a lot! Dankon!