做一次心电图多少钱:two and a half hours' walk可不可以说two hours and a half's walk

two and a half hours' walk可不可以说two hours and a half's walk 请问“两个半小时”是“two and a half hour”还是“tow and a half hours”？ two and a half month(s),month后加不加s two and a half month(s),month后加不加s？？ “两年半”译为“two and half years”与“two and a half years”是否都是正确的？ It’s now exactly half past seven. _______ , the doctor has been here for two hours. one-and-a-half 是什么意思？请进 Two hours 是什么？ He walked on for another two hours and arrived there at last.同义句 Jack spends two hours _____housework.