恐龙在距今约6500万年前灭绝，那时距离下一个千年还有很久。

Dinosaurs went extinct about 65 million years ago, long before the next ___millennium.

许多人期待着未来的千禧年，那时疾病将被彻底消除。

Many people look forward to a future ___millennium when diseases will be completely eradicated.

我们正在计划举办一场盛大的千禧年庆典。

We are planning a grand ___millennium celebration.