every once a while ,every once and a while有什么区别?

题目

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.

答案

every once a while:每时每刻
every once and a while:隔一阵一次,时常