变形词有frequent 频繁的；frequence 频繁；frequency 频繁性；frequencies 频率，例如：
1.Buses run frequently between the city and the airport.公共汽车频繁地来往于市区与机场之间。
2.His name features frequently in the social columns of the tabloid newspapers.他的名字频繁地出现在各种小报社会专栏的显著位置上。
3.Save data frequently.资料要经常存盘。
