1. That's what a keystone species does in an ecosystem. 那就是拱顶石物种在生态系统中的作用。
2. The government's determination to beat inflation has so far been the keystone of its economic policy. 政府对通货膨胀的坚决抑制迄今为止一直是其经济政策的根本。
3. It might seem that certain traits would clearly define a species as a keystone species. 似乎某些特征会清楚地将一个物种定义为关键物种。
4. In architecture, a keystone in an archway or doorway is the stone that holds the whole thing together, and keeps it from collapsing. 建筑学中，拱道或门口的拱心石，是把建筑整体连接在一起来防止它倒塌的石头。
5. Because complex species interactions may be involved, identifying a keystone species by removing the species and observing changes in the ecosystem is problematic. 由于其中可能涉及复杂的物种相互作用，通过移除一个关键物种并观察生态系统的变化来确定该物种是有问题的。
