uncommon

It is uncommon for snow to fall in this tropical region, but a rare cold front brought a light dusting yesterday.

(Chinese) 在这个热带地区下雪是很罕见的，但昨天一个罕见的冷锋带来了薄薄的一层积雪。

The doctor noted that the patient had a very uncommon blood type that would make finding a donor difficult.

(Chinese) 医生注意到患者有一种非常罕见的血型，这将使寻找捐献者变得困难。