a half hour还是half an hour?

a half hour还是half an hour? an hour and half还是an hour and a half 是half hour还是half an hour? half an hour or a half hour? a half of an hour half an hour 和a half hour有什么区别? a half hour later\after half an hour\after half an hour late one and a half hour看做单数还是复数?half an hour half hour =half an hour half an hour,half hour,a half hour哪些对,那些错 half an hour later half an hour?