A suntan, she explained, was a defensive skin reaction to produce more of the pigment melanin to protect itself from too much harmful ultraviolet (UV) radiation.是什么意思_A suntan, she explained, was a defensive skin reaction to produce more of the pigment melanin to protect itself from too much harmful ultraviolet (UV) radiation.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句