half an hour 和a half hour有什么区别?

half an hour 和a half hour有什么区别? One and a half an hour 和An hour and a half 有什么不同 half an hour or a half hour? a half hour还是half an hour? a half of an hour an hour and half还是an hour and a half Half an hour =什么? half an hour? 什么意思? half an hour 与 one half hour区别 a half hour later\after half an hour\after half an hour late 是half hour还是half an hour? half hour =half an hour