Ask one of Jehovah's Witnesses

[Tonus]

Do the JW's have an explanation for Jesus' statement that one of this generation (meaning his) will still be alive when the kingdom comes?

The belief is that Jesus' statement, like a few others, applied to both his present and our future. The JW leadership used it as a way of implying and end date without having to be specific. Their initial claim was that the "generation" of people who "witnessed" the events of 1914 would not pass until the end came. That allowed them to promote the idea that the end was very close in the 70s and very very close in the 80s. But as time passed with no sign of the end, they began to modify the interpretation of the prophecy (or more accurately, their interpretation of their interpretation of the prophecy) to give themselves a bit more room to work with.

This page explains it in more detail. In short, their final attempt to square the circle is to claim that the "generation" includes those who knew some of the people who witnessed the events of 1914. This allows them to stretch the possible date of the end another 70 or 80 years, at which point I'm sure they'll find some "new light" that will provide another few decades during which the end of the world will be right around the corner.