unique 前面用a定an??

Should be "a unique"...

When "u" word is pronounced as though it begins with a "y" (yoo nique), it's treated more like the consonant sound of the "y". So, "a university," "an umbrella", "a usual day", "an unusual day."

Hope it helps.

用a先係correct
因為unique發的音係yoo,唔係我地一般讀umbrella,unusual既un音
正如我地會讀a university, not an university
an hour也是同樣原理

因為a,e,i,o,u
所以unique係an