As we age, our skin becomes less effective at converting sunlight to vitamin D.

随着我们年龄的变老，我们的皮肤在转换阳光到维他命d的能力也越来越弱。

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As we age, our skin becomes less effective at converting sunlight to vitamin D.

随着我们年龄的变老，我们的皮肤在转换阳光到维他命d的能力也越来越弱。

youdao