half an hour=?（两个单词）

half an hour=?（两个单词） half hour =half an hour Half an hour =什么? half an hour later half an hour? 是half hour还是half an hour? half an hour or a half hour? a half hour还是half an hour? he spent half an hour swim.=It( )( )half an hour( )( ). an hour and half还是an hour and a half half an hour or hour中文 half an hour? 什么意思?