Slow, continuous change may be the norm during periods of environmental stability, while rapid evolution of new species occurs during periods of environment stress.
缓慢的、持续的变化可能是环境稳定时期的常态，而新物种的快速进化发生在环境压力时期。
2
Nor should policy disputes be used as an excuse to undermine the stability and evolution of the relationship.
政策上的争议也不应当被用作破坏双方关系稳定及妨碍其进展的口实。
3
The existence of so many neighbours suggests that planetary systems tend to be stable, and stability is good for the evolution of life.