You use extreme to describe situations and behaviour that are much more severe or unusual than you would expect, especially when you disapprove of them because of this.
过激的 The extreme case was Poland, where 29 parties won seats. 过激的案例是波兰,那里有29个政党获得席位。
You can use extremes to refer to situations or types of behaviour that have opposite qualities to each other.
极端 go to extremes