UV is short for ultraviolet. It is a kind of light your eyes cannot see, sitting just past the violet end of the rainbow — that is exactly what "ultra-violet" means: beyond violet.

UVUV is short for ultraviolet是紫外線的縮寫. It它 is a kind of light your eyes cannot see是一種你眼睛看不到的光 sitting just past the violet end of the rainbow剛好在彩虹紫色那端之外一點點 — that is exactly what「ultra-violet」means這正是「ultra-violet」這個字的意思: beyond violet超過紫（色）

It comes from the sun, and it is the part of sunlight that tans your skin, burns it, ages it, and over years can cause skin cancer. It is also what makes glow-in-the-dark posters glow and what banknote checkers shine on money to see the hidden marks.

It它 comes from the sun來自太陽 and it is the part of sunlight而且是陽光裡 that tans your skin, burns it, ages it會讓你皮膚曬黑、曬傷、老化的那部分 and over years can cause skin cancer而且經年累月可能導致皮膚癌. It它 is also what makes glow-in-the-dark posters glow也是讓夜光海報發光的原因 and what banknote checkers shine on money to see the hidden marks也是驗鈔機照在鈔票上看隱藏記號用的東西

In everyday English "UV" is used three ways. As a noun: "too much UV is bad for you." As an adjective before another noun: "UV light," "UV rays," "UV protection," "a UV index of 11." And in fixed labels you will see on products here in Taiwan: "UV cut," "anti-UV," "UPF 50+." People say the two letters separately, "you-vee," never "uhv." One thing worth knowing: UV goes through clouds and glass differently from ordinary light, which is why you can burn on a grey day and why drivers get more sun damage on one arm.

In everyday English在日常英文裡「UV」「UV」 is used three ways有三種用法. As a noun當名詞用: 「too much UV is bad for you.」「too much UV is bad for you.」（太多 UV 對你不好） As an adjective before another noun當形容詞放在另一個名詞前面: 「UV light,」「UV rays,」「UV protection,」「a UV index of 11.」像「UV light」、「UV rays」、「UV protection」、「a UV index of 11」. And in fixed labels you will see on products here in Taiwan而在台灣的產品上你會看到的固定標示裡: 「UV cut,」「anti-UV,」「UPF 50+.」有「UV cut」、「anti-UV」、「UPF 50+」. People say the two letters separately大家會把這兩個字母分開唸,「you-vee,」never「uhv.」唸成「you-vee」，不會唸成「uhv」. One thing worth knowing有一件事值得知道: UV goes through clouds and glass differently from ordinary lightUV 穿過雲層和玻璃的方式跟一般的光不一樣, which is why you can burn on a grey day and why drivers get more sun damage on one arm這就是為什麼陰天也會曬傷、也是為什麼司機一隻手臂常常曬得比較嚴重的原因

That is why the weather report gives a separate UV index from the temperature — a cool day can still be a high-UV day.

That is why這就是為什麼 the weather report gives a separate UV index from the temperature氣象報告會把 UV 指數跟氣溫分開列出來的原因 — a cool day can still be a high-UV day涼涼的一天，UV 指數還是可能很高