TD, good find. last night I was looking at the greek text too, and it appears that the word "occur" in verse 34 has the same root as "generation", so, It seems natural then, that wt (and as sparky1 mentioned) we here too, can "generate", or have occurr to us, various definitions of the generation.
if even one of the "generation" is left standing, which is not at all what the Jesus character actually said.)
TD: yes, your idea is supported by the context, in verse 37 referring to the near mass extinction, triage of all those present during the flood. on the broader theme:
wt illustrations like the KR book, page 225 shows their "anointed generation" lasting until the battle of Armageddon, so the time line includes more than just the sign, but all what the Jesus character mentions after verse 34, with that emphasised negative. Amazingly his speech concludes, the last word, with zoen aionion , life everlasting, emphasising the "no, not passing" for the generation, which, according to chapter 25 would be the Sheep, rather than the anointed "brothers of Christ" exclusively.
The generation does not pass after the sign, it does not even pass after Armageddon, it can not possibly the wt shortened anointed generation.