periodic

工厂进行定期检修，以确保设备安全运行。

The factory conducts ___periodic maintenance checks to ensure equipment safety.

我们需要定期进行设备检查以确保安全。

We need to conduct ___periodic equipment inspections to ensure safety.

化学老师让我们研究元素周期表中元素的周期性变化规律。

Our chemistry teacher asked us to study the ___periodic patterns in the table of elements.