a half 是多长时间.谢谢

a half 是多长时间.谢谢 ----- were you there ?---Half a month.谢谢!``~ half cup a half cup half a cup 那个正确?half cup ,a half cup ,half a cup 那个正确?半杯.那个表达对名词一般是放在 half half cup half a cup 那个更好 是a half hours还是a half hour?a half后面是单数还是复数啊? 须臾是多长时间a half的用法是 one and a half years 还是one and a half year?half具体的用法? half a a half half a a half half a world away 的意思是? 什么叫半衰期英文是half-life,谢谢 at half a price/at half price/at a half price哪个是对的哪个是错的...为什么 是one year and a half还是a year and a half?为什么? 注意是：one and half 和 one and a half区别注意是：one and half 和 one and a half．他们有什么区别吗? “半个月”用英语怎么说?是half mouth?还是half a mouth?还是half of mouth?还是half of a mouth? 是one and a half hours还是one and a half hour 是one and a half hour 还是 one and a half hours