a white umbrella 还是 an white unbrella?

a white umbrella 还是 an white unbrella? 是 a umbrella还是an umbrella,为什么? ( )blue umbrella ( )里是填a还是an? I have_____beautiful umbrella 括号里是加a还是an a white night,a white crow,white 英语形容词排列a white old car还是a old white car 请说明原因 he said with a white face 对还是in a white face a white A white a white a white a White a white uniform 前加的是a还是an ,哪umbrella 呢 a hand--free umbrella 意思 字母u前用a还是an?There is ___ u in the word umbrella.用a还是an? the cat is black and white对不对 还是the cat is black-and-white 还是the cat is a black-and-white cat很急的,今晚就要, have you seen an umbrella here? ____black one?it was here minutes ago.这个空该填a还是the?