every和once 有什么区别啊?例如every two days 和once two days

every和once 有什么区别啊?例如every two days 和once two days every和each有什么区别啊 one time和once有什么区别? once 和the moment有什么区别? every once a while ,every once and a while有什么区别?给两个句子,I JUST WANT U TO SAY IT EVERY ONCE A WHILE.EVERY ONCE AND A WHILE I SCREAM STUFF AT THE TV. once in a while与every once in a while有什么细微区别,后者更频繁些?谢谢了 every和once的用法区别奥运会四年举办一次是：The Olympic games are held every four years.但是能不能说：The Olympic games are held once four years.有没有什么特定的规则呢? 有首歌叫什么day~once more其中有什么every every~ every day和everyday有什么区别 every和any有什么区别 every two days 和every second day有什么区别 every body和every person有什么区别? every body和every person有什么区别? once time 和 first time 有什么区别、 in a minute 和 at once 有什么区别 英语：at once和at that moment 有什么区别? once a year in Japan和in Japan once a year有什么区别么? once more,one more time和once again有什么区别once moreone more timeonce again都是再一次的意思?