happening often; habitual
"a frequent guest"
"a frequent (or common) error is using the transitive verb `lay' for the intransitive `lie'"
"She haunts the ballet"
Walls..flanked and crowned by frequent square towers.
出自： M. B. Keatinge
This University City, which is frequented..by thousands of students.
出自： A. J. Toynbee
Castle..entered a bookshop he had frequented for several years now.
出自： G. Greene
误 The motoring accidents are frequent to happen at this crossroad.
正 The motoring accidents are frequent at this crossroad.
析 frequent所表达的“频繁”这一概念,它本身已含有“发生”的意思,所以加用to happen这样一个不定式是多余的。