1. His face was smooth and ageless.
    他的脸光洁，不显老。

2.

2. The origin of the universe is an ageless topic.
    关于宇宙的起源的问题是个永恒的论题。

1. 不老的：ageing 成熟 | ageless 不老的 | agelong 持续的

2. 不会老的：ageism 年龄主义 | ageless 不会老的 | agency 能量

3. 永不衰老的：happy 快乐的 | ageless 永不衰老的 | noble 高贵的

1. 永不衰老的
    If you describe someone as ageless, you mean that they never seem to look any older.

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    e.g. She was rich, beautiful and seemingly ageless.
           她富有而美丽，永远显得那么年轻。

2. 永恒的；长存的；古老的
    If you describe something as ageless, you mean that it is impossible to tell how old it is, or that it seems to have existed for ever.

    e.g. ...the ageless oceans.
           古老的海洋

1. continuing forever or indefinitely

    e.g. the ageless themes of love and revenge
           eternal truths
           life everlasting
           hell''s perpetual fires
           the unending bliss of heaven

    Synonym: aeonianeonianeternaleverlastingperpetualunendingunceasing