周期性地

The geyser erupts periodically.

间歇泉周期性地喷发。

Economic crises recur periodically.

经济危机周期性地发。

In eastern China, transgression occured periodically during Eogene, and formed specially paleobio-cenosis,mineral association and rock type.

在中早第三纪沉积演化程中曾周期性地发海侵,从而形成了具有海相特征的岩石类型、组合。