They are asking you about the Last Hour as: "When will It take place". You say: "Indeed, the Knowledge about it is with my Lord, He doesn’t disclose its time except with Him. It will be heavy in the heavens and earth, it will not come to you except all of a sudden". They are asking you just like you are solicitous about it. You say: "Indeed, its Knowledge rests only with Allah, but most of the people are not having the Knowledge".
It is told in verse 33: 63: "People ask you concerning the Last Hour. You say that the Knowledge about it is only with Lord, and what may make you perceive? Perhaps the Hour is near". It is told in verses 54: 49-50: "Indeed, Lord has created all things with predestination and His Command is but one, like a glance of the eye". It is told in verses 36: 49-50: "They don't await except one blast which will seize them while they are disputing, and they will not be able to give any instruction, nor they can return to their people". The Three-Time-Knower Lord has already decreed and prescribed in Adhikr whatever things happen in the universe as explained in verse 2: 255. All 313 Messengers are sent down with Adhikr as explained in verse 4: 163.
Today Adhikr is codified as the Best Interpretation of the Lord's Book. So, if anyone doubts about any matter should ask the Three-Time-Knower mentioned in verse 25: 59 who is the author of Adhikr. Last Hour will not happen until the Ten Crucial Signs which will occur only after the departure of the last forerunner from the earth as explained in verse 6: 158. See explanation 4: 158-159; 6: 59, 123-124; 7: 127, and 137.