cleaning frequency

例句：

1. 1.The cleaning frequency of the machine is 2 hours per week.
   这台机器的清洗频率是每周两次。
2. 2. The frequency of the earthquakes in this area is increasing.
   这个地区的地震频率正在增加。
3. 3.The frequency of the traffic lights is reduced to save time.
   为了节省时间，交通灯的频率被降低了。