from time to time

from time to time

时常，有时，不时

from time to time是 time 的常见短语，是一个表示频度的介词短语，其频度和 at times， sometimes ，now and then是同意表达，都表示“有时”的意思。

from time to time=sometimes=at times=now and then

频度比较

always>usually>often>from time to time>occasionally>seldom>hardly

例句：

1. She sat silently,flinging the odd word into the conversation from time to time.

她静静地坐着听谈话，不时插进一两句。

2. He threw in a word or two from time to time.

他时不时冒出一两句话。