她以每小时50英里的稳定速度驾驶。

She drove at a steady 50 mph.

《牛津词典》

或者，稳定性可以被定义为生态系统在发生重大扰动，如一场火灾后，恢复到特定形式的速度。

Alternatively, stability can be defined as the speed with which an ecosystem returns to a particular form following a major disturbance, such as a fire.

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他们认为岛上的人口增长迅速，然后保持或多或少的稳定速度来增长，直到欧洲人的到来引进了岛上居民对其没有免疫力的致命疾病。

They think its population grew rapidly and then remained more or less stable until the arrival of the Europeans, who introduced deadly diseases to which islanders had no immunity.

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