在我们的一生中，我们将看到大量的技术变化。

We'll see a tremendous lot of technological changes during/in our ___lifetime.

比赛的获胜者将获得一生难得的假期。

Winners of the competition will receive the holiday of a ___lifetime.

婚姻不再总是被视为一生的承诺。

Marriage is no longer always seen as a ___lifetime commitment.