"Ĉu ili iam manĝas je tagmezo?"
Translation:Do they ever eat at noon?
Not really. "At noon" is translated to "je tagmezo", but "je" does not mean "at".
"Je" doesn't have a specific meaning. It is a preposition that is used when no other preposition makes literal sense. Let's take "ĉe" as an example. It refers to a physical location that one is "at", but one can't physically be "at" a time (or "over", "under", "in", "beside", etc.) so we use "je".
Quoting salivanto from an earlier comment on this same sentence: "Not quite 'substitute any preposition.' More like 'it's the preposition to use when no other preposition is applicable.'"
Also, I've always heard this so I'll pass it on to you: it's better to learn the uses of "je" rather than trying to logic it out. Some Esperanto phrases use a different preposition when it SEEMS that "je" would make more logical sense.
That is not at all true, j is an approximate (a form of consonant) requiring a partial obstruction of air. i is a vowel, fairly closed and frontal. Check out some phonetics to help clear up the differences if neede, its hard to explain in text but the biggest differences are the obstruction and the voicing.
No, @tacit-blue is right. "voiced palatal approximant" and "close front unrounded vowel" are just two different ways to describe the same configuration of mouth & throat. The only difference between [i] and [j] is that [i] appears in the nucleus of a syllable.
"Do they eat at noon sometimes?" is the so called correct answer, but I see a different translation here as "Do they ever eat at noon?" Question: Is this alternate translation included in the software for the answer for this exercise? BTW I find the "Do they ever eat at noon" to be a much better translation than the "correct" answer I see in the program. "Do they eat at noon sometimes" sounds like a non English speaker translation.
I can confirm "ever" is accepted. But i will point out in english "do the eat at noon sometimes" has a different meaning than "do they ever eat at noon". Do they eat at noon sometimes? Yes. -This implies they ate at noon infrequently but more than once. Do they ever eat at noon? Yes. - Only confirms the question, not the frequency. Could be once, regularly, every day....
I would say one of these translations must be wrong, but they are both accepted here.