a half mile 还是half a mile

a half mile 还是half a mile my old house is about..My old house is about _____from here.A.half of a mile B.half a mileC.a half of mile D.half mile a half apples还是a half apple a half hour还是half an hour? She ran a half mile in a half hour.上面这个句子两个a可以放在half后面吗? 改错:she rans half a mile in half an hour.嘻嘻..我英语太烂了 half a a half half a a half in half a price还是 at half a price? half a million of trees还是half a million trees half an apple 还是a half apple还是都可以 是a half hours还是a half hour?a half后面是单数还是复数啊? half a dozen sheep race down hill over a course of about half a mile怎么翻译好? one and half还是one and a half an hour and half还是an hour and a half She ran a half mile in a half hour.中a可以放在half吗?为什么 为什么为什么为什么为什么~~~`