Bunyip
pro scapegoat
If that verse is read in context of the entire passage I think it is clear that Jesus is speaking in reference to a future generation, the generation which sees the signs He has just finished speaking about. It is this generation which will not pass away and will see His return. I believe one of the most indicative signs is that of the re-establishment of the nation of Israel.
That makes no sense at all, why would he speak to the generation in front of him but really be meaning some future generation as yet unborn? Clearly he meant that some of those listening would still be alive when he returned - and of course he did not.