in the swim
1．doing the same things that other people are doing做别人正在做的事；随大流
Jim found some college friends at the lake that summer and soon was in the swim of things．那年夏天吉姆发现他的一些大学同学在湖边度假，于是他很快加入到他们的活动中去。
2．following fashion赶时髦
Mary went to the city and found girls were dressed in green，and soon she was quite in the swim．玛丽去那座城市，发现姑娘们都穿绿色的衣服，于是很快也赶上了潮流。