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。