I compared the reasoning book with their latest info in the Insight online:
Last Days
Definition: The Bible uses the expression “last days” to refer to the concluding time period leading up to a divinely appointed execution that marks the end of a system of things. The Jewish system with its worship built around the temple in Jerusalem experienced its last days from 33 to 70 C.E. What occurred then was pictorial of what would be experienced in a greatly intensified way and on a global scale at a time when all nations would be facing the execution of judgment decreed by God. The present wicked system of things, which extends worldwide, entered its last days in 1914, and some of the generation alive then will also be on hand to witness its complete end in the “great tribulation.”
Later that same day, Jesus again used practically the same words, saying: “Truly I say to you that this generation will by no means pass away until all these things occur.” (Mt 24:34) In this instance, Jesus was answering a question regarding the desolation of Jerusalem and its temple as well as regarding the sign of his presence and of the conclusion of the system of things. So his comment about “this generation” logically had an application down to 70 C.E. However, he was also using the word “generation” with reference to humans whose lives would in some way be associated with the foretold events during his presence.—Mt 24.