In their study, the researchers tested itamin D3, or cholecalciferol, the kind humans make when they are exposed to sunlight.是什么意思_In their study, the researchers tested itamin D3, or cholecalciferol, the kind humans make when they are exposed to sunlight.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句