an hour pass by

an hour pass by half an hour ___(pass) since the train __(leave) Half an hour ____(pass) since the train __(leave). Peter's home is an hour by bus from the city center.对an hour hour by hour it usually______her half an hour to go home by bus. our school is "abot half an hour by bike" The play for half an hour by the time an hour one hour pass与 pass by区别 It's only( )by bus.A half an hours' B half an hour's C half a hour 还是 an hour?