infrequently
adv. 很少发生地；稀少地
例句
The bridge is used infrequently.
这座桥很少有人用。
《柯林斯英汉双解大词典》
This is a problem not infrequently encountered by postdocs.
这是一个博士后学生经常遇到的问题。
You are more liable to injury if you exercise infrequently.
不经常运动就更容易受伤。
《牛津词典》
