half hour =half an hour half hour half an hour 的意思有和区别?

half hour =half an hour half hour half an hour 的意思有和区别?
half hour =half an hour
half hour half an hour 的意思有和区别?

half hour =half an hour half hour half an hour 的意思有和区别?
数量上的区别.如果在half an hour前面加上个数量词比如ONE\TWO这样的数量词就变成了*个半小时了.half hour则特指半小时.