less hours 还是 fewer hours 哪个是正确的?

less hours 还是 fewer hours 哪个是正确的? People who sleep ___ six hours a day.是填fewer than还是less than We shouldn't sleep[ ] than eight hours a night.是 less 还是 fewer为什么? money用less还是 fewer fewer words 还是less words less and less children 还是fewer and fewer childern? 为什么是less than three hours 不是 fewer i slept for ( ) 7 hours last night ,是填less than 还是fewer than 老师讲的是less than, 为什么? less than two hours 还是fewer than two hours从语法角度,该是后者,为何实际中碰到了前者,晕,该如何说服学生呢? 是less people 还是fewer people? less fast food还是fewer fast food few的比较级是fewer还是 less? ( )leisure time用less还是fewer few的比较级是fewer还是 less? green trees前用less还是fewer 形容food 用less 还是用 fewer是less food 还是 fewer food 越来越少 汉译英 less and less 还是fewer and fewer 是形容朋友越来越少的. 树变的越来越少 英语RT到底是less and less 还是fewer and fewer?