是a还是an

是a还是an This is___yellow orange,是a还是an 一个MP4 英文翻译是a还是an 是 a umbrella还是an umbrella,为什么? EUROPEAN WOLF是用A还是AN 是a还是an university student? 是a unusual还是an unusual 是a unusual还是an ununusal? European是搭配an还是搭配a 是an one还是a one 是an experience还是a experience 是a man还是an man _____American boy是填a还是an eraser前面是加a还是an 是an body还是a body interesting,的定冠词是a还是an advice前面是加a还是an 是an ID card还是a