1)first-order cycle,一级周期2)third-order cycle,三级周期3)one year cyclic vibration,一年周期4)one-period,一(个)周期5)in the course of a week,一周期间6)bus cycle accuracy,周期精确级
用法和例句
The variation of ozone density is of an obvious one year cyclic vibration, shown as the seasonal variation.