keystone [ˈki:stoʊn]

例句:

• Keeping inflation low is the keystone of their economic policy.
  将通货膨胀率保持在较低水平是他们经济政策的主旨。
  来自柯林斯例句
• Social justice is the keystone of their political program.
  社会公平是他们政治纲领的基本原则.
  
• Quantitative measurements of one sort or another serve as the keystone of engineering practice.
  定量测定一种或多种成分是环境工程中的重要项目.
  
• Keystone XL is a step in the right direction.
  来自WSJ
• A terrible title for giving away the story's keystone line.
  来自NEWYORKER
• Coyotes act as keystone predators in some systems and mesopredators in others.
  来自SA