unprecedented and unrepeatable; unique

• 空前绝后

unprecedented and unrepeatable; unique的用法和样例：

例句

1. It's unprecedented and unrepeatable.
   这是空前绝后的。
2. That was probably an unprecedented request on the part of a Reich minister.
   一个帝国的部长提出这样的要求，恐怕是空前绝后的。