火力大小自由调节，而持续稳定。
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。
Slow, continuous change may be the norm during periods of environmental stability, while rapid evolution of new species occurs during periods of environment stress.
此区域中的稳定力量之一是美国的持续介入，而美国——常被指责忽略了欧洲——理应被赞颂。
One force for stability in the region is continued American engagement, for which the United states-often accused of ignoring europe-deserves praise.
应用推荐