happening or recurring at regular intervals;"the periodic appearance of the seventeen-year locust"
recurring or reappearing from time to time;"periodic feelings of anxiety"
中英词源
periodic 周期性的
来自period,周期，时期。
periodic (adj.)
1640s, from French périodique (14c.), from Latin periodicus, from periodus (see period).
Periodic table in chemistry (1889) is from notion of the arrangement, in which similar properties recur at intervals in elements in the same area as you read down the rows of the table. This sense of the word is attested from 1872 (periodic law).
词态变化
副词 periodically;
权威造句
1. There may be periodic police "sweeps" of crime in the area.
警方可能对该地区的犯罪活动进行定时的“扫荡”。
来自柯林斯例句
2. Periodic checks are carried out on the equipment.
设备定期进行检查。
来自《权威词典》
3. Long long ago, we knew the periodic motion of a planet.
很久以前, 我们就知道行星的周期运动.
来自《简明英汉词典》
4. These arrangements are subject to periodic reviews.
这几项安排每隔一定时间须予复查.
来自《现代汉英综合大词典》
5. Periodic checks are taken to ensure that high standards are maintained.
