every now and then是什么语法现象 特别不知道every在这干什么?

every now and then是什么语法现象 特别不知道every在这干什么? every now and then是什么意思? now and then 与 every now and then 的区别是什么? 请问now and then和every now and then again意思分别是什么? every now and then 还是 now and then?表示不时? I see him every now and then,but not often.这里的every是什么用法? Every now and then和once in a while I our daily life,everyone fails every now and then 英语翻译Regressing---looking back every now and then at somethin Every now and then sunshine is warm making life extremely now and then和every now and then的意思完全相同吗? every now and then和now and then 有什么区别?