every now and then和now and then

every是用来表示强调的.

every now and then

=from time to time； occasionally 不时；时常

*Every now and then I
like to walk along the beach and forget my problems．我常常喜欢沿着海滩散步，忘记我的问题。

*I meet him every now
and then on the street．我时常在街上碰见他。

now and then

=now and again；occasionally；once
in a while时而；偶尔

*Now and then he goes to
a ball game．他偶尔去看看球赛。

*Now and then Larry and
his wife go out to dinner at an expensive firstrate restaurant．拉里和他妻子偶尔去豪华饭店吃饭。

*Every now and then she
would glance up at the clock．她不时抬头看看钟。