half a year .a half year可以么?

half a year ago. half a year .a half year可以么? once half year,twice a year half a a half half a a half three years and half a year half的用法是 one and a half years 还是one and a half year?half具体的用法? one year and a half和a year and a half哪个正确 是one year and a half还是a year and a half?为什么? The johns stayed in HeFei （ ）.A.for half a year B.half a year ago 有half a year 的说法,那有没有a half year 的说发? A.one and a half year`sB.a year and a half`sC.one and a half yearD.a year and a half的区别和用法A.one and a half year`sB.a year and a half`sC.one and a half yearD.a year and a half one year and a half 和 one and a half years thanks! one () and a half one and a half () years or year? a half apples还是a half apple a half与half a的区别