When the skin is exposed to sunlight, the radiation triggers the formation of free radicals which, in turn, damages the DNA in skin cells, causing tumours to grow.

• 当皮肤暴露在阳光下，紫外线辐射会引发游离原子团的形成，转而破坏皮肤细胞中的DNA，引起肿瘤的生长。