skin pigment短语¹⁸⁰⁰⁹⁸⁺¹ 基本例句 皮肤色素 Scientists have long known that vitamin D is a vital nutrient that the skin produces when hit by sunlight. The amount varies, depending on where the person lives, skin pigment, age and other factors. 科学界的共识是,人的皮肤可以通过日晒产生维生素 D.而产生的数量并不固定,这取决于人所在地,皮肤的状况,年龄以及其他的因素. yeeyan