Although most of the effects of UVB are harmful, the rays perform one indispensable function: initiating the formation of vitamin D in the skin.
Although most of the effects of UVB are harmful, the rays perform one indispensable function: initiating the formation of vitamin D in the skin.
虽然UVB对皮肤的影响大部分都是有害的，这种射线却能执行一种不可或缺的功能：促成维生素D在皮肤中形成。