持续一个小时是last one hour还是last for one hour,还是两个都行

持续一个小时是last one hour还是last for one hour,还是两个都行 a one -hour还是an one-hour 是a one-hour ducumentary还是an one-hour documentary 冠词 an one-hour 还是a one-hour 是one and half hours还是one and half hour? 一个半小时 英语：是one and a half hour 还是 one and a half hours Marcia skated()in last year's marathon.A.for one hour B.for one half hour 到底是半小时还是1个半小时 one and a half hours 还是hour No one had stopped to help her for the last hour,had he? Yes I s______ one hour doing my homework last night one hour和an hour,两个是无差别的吗?