循环

circulate;circle;cycle;circular;rotary;revolving
一个人有动脉、静脉，通过心脏进行血液～。A man has arteries and veins through which the heart circulates blood./～不息move in endless cycles/～往返move in cycles/恶性～vicious circle/良性～virtuous circle;selfsustained growth/～基金revolving fund/～系统circulatory system/～信贷revolving credit/～信用证revolving credit/～一体化circular integration /～支票circular check /～经济circular economy/～赛round robin（体育运动）