periodically

副词 periodically:

1. in a sporadic manner
   同义词：sporadically

1. A device that periodically and automatically opens and closes an electric circuit, producing pulses.
   断续器一种阶段性的能自动打开及关闭电路并产生脉冲的仪器
2. New strains of viruses appear periodically.
   新菌系的细菌周期性地产生