Non-Jesus Verse: Matthew 24:3 The Apostle's Question
The Greek of this verse is translated because of its importance in the coming discussion about the culmination of the era. There are a number of key mistranslations in it.
The word "sign" in its verse is not a mistranslation, but the Greek word specifically means a sign from the gods and that sense, it means "omen," "portent," and "constellations," but it also means a "proof" in reasoning. The translation of "proof" often seems how Jesus uses it. Here the word seems to have the sense of "significance" in "omen" and "constellation" connects with the references in Matthew 24:27 and Matthew 24:31 to a "comet," this sight of which were considered omens. This same word, a "sign" or "omen" shining in the sky is used in Matthew 24:30, likely referring to the comet in Matthew 24:31. But in that verse, "comet" is translated as "trumpet," demonstrating that the translators missed the entire point of these verses.
The word translated as "coming" does not refer to a second coming. The word means "presence," "arrival," but in the sense of "having arrived," "occasion," "situation," "substance," "property," and "contribution." It is an uncommon word, only used by Jesus three times in this section of Matthew. It is first used in this verse by his students, not by Jesus himself. They cannot be thinking about some future arrival. He is there now, predicting the destruction of the Temple. It has nothing to do with the verb usually translated as "coming." It is from the present participle of the verb meaning "to have arrived" and "to be present." Jesus is with them, what does his presence mean in regards to the Temple being destroyed?
The word translated as "end" means literally "to bring together for a goal." It means the accomplishment of a shared purpose, so "culmination." It does not mean "end" in the sense of "destruction" of anything since it has the opposite sense of "accomplishment." Yes, the temple is being destroyed, but Jesus's students see this as a bringing together of historical purpose since they believe the Divine has a purpose. There is no definite article before this word, so not "the culmination" but "a culmination." The "the" is added to make it sound like the definitive end of things, which is not what the apostles thought.
"World" is from aiôn, which means "lifetime," "life," "a space of time," "an age," and an "epoch." The students seem to be using it as an "epoch," marked by the end of the second temple as the destruction of the first temple culminated an earlier epoch of Israel as an independent nation, that destruction earned by the failure of its kings. However, in his response, Jesus plays with this word, using it to refer to what happens at the fall of Jerusalem, any time of crisis, and the death of a person. See this article on words translated as "world" in Jesus's words.