钻石因其永恒的光泽而备受珍视。

Diamonds are treasured for their ___everlasting brilliance.

他们之间永恒的友谊经受了时间的考验。

Their ___everlasting friendship has stood the test of time.

这个演讲似乎永无止境，我们都开始感到无聊了。

The lecture felt like an ___everlasting ordeal, and we all started to feel bored.