periodical change

例句：

1. 1. The magazine has a monthly circulation of 500,000 copies.
   这本杂志每月发行量为50万份。
2. 2. The weather patterns are cyclical, repeating every few years.
   天气模式是周期性的，每隔几年就会重复一次。
3. 3. The team practices regularly to maintain their periodical performance.
   该团队定期训练以保持他们周期性的表现。