at intervals

1.It snowed at intervals this week.

这星期不时下雪。

2.These cars are put at intervals of three meters.

这些车每隔三米放一辆。

3.Flaming torches were positioned at intervals along the terrace.

沿台阶每隔一段距离布置有燃烧着的火炬。

4.The UIE hold a large scale international academical congress at intervals of four years.

摘要国际电热会(UIE)每隔4年举行一次大规模国际性的电热学术会议。