It is not uncommon for …

结构︰

It is not uncommon for＋名词＋to-不定词…

说明︰

此句型意为“…并非不常见”。not uncommon 是双重否定，表肯定。it 是虚<主语>。

It is not uncommon for parents to put a newborn in a separate room.
父母把新生儿放在分隔的房间并非不常见。
It is not uncommon for women to smoke in public.
妇女在大众面前抽烟并非不常见。
It is not uncommon for people to jaywalk.
人们任意穿越马路并非不常见。