生僻的英文：
uncommon; rare

uncommon是什么意思：
adj. 不常有的，罕见的；非凡的

Collusion of the police with the criminal is not uncommon
警察和罪犯串通是常有的事情。

The sun was shining with uncommon lustre.
太阳放射出非凡的光彩。

Collusion of the police with the criminal is not uncommon.
警察和罪犯串通是常有的事情。

It is uncommon for healthy animals to cast their young.
健康的小动物小产是不寻常的事。

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。

rare是什么意思：
adj. 稀罕的；珍贵的，极好的；半熟的

I will have a cheeseburger, medium rare.
我要一份起士汉堡，五分熟。

I rarely have short drinks.
我很少喝烈性酒。

Journalists are rarely admitted to the region.
新闻记者很少获准进入该地区。

Economic collapse is a rare circumstance.
经济崩溃是不太可能发生的事。

It is very rare for Jeanne to be late.
珍妮很少迟到。