A square has four sides but a circle has no sides.
正方形有四条边，而圆形没有边。
I need experience to get a job but without a job I can't get experience it's a vicious circle.
我得有经验才能找到工作, 可是没有工作我就无法获得经验--这真是个恶性循环.
He is part of an exclusive social circle and belongs to an exclusive club.
他所处的社交圈子很排外，而且参加的又是个很排外的社团。
