一成不变 [- - bú biàn]immutable and frozen; be immutable; be set in one's ways; changeless; cut and dried; fixed and unchangeable; go into a rut; hard and fast (formula etc,); inflexible; invariable; monotonous; unchangeable; unalterable:
•¶一成不变的东西是没有的。 Nothing is changeless.
•¶ 世界没有一成不变的东西。 Nothing in the world is immutable.