every four years 与 every third year every fo

every four years 与 every third year every fo every third year与every three years的区别 every year 与every years very four years every other year every few years every fourth year和every four years一样吗 every four years和every fourth year一样吗? every other three years every four years 和every fifth year相等 every 2 year?every 2 years? every third every four years代表什么 every four years等于three? every four years什么意思?