frontiers

例句:

• Community leaders want to strengthen controls at external frontiers.
  社区领导想要加强对小区外围的管理。
  来自柯林斯例句
• Pushing the frontiers of exploration requires co-operation for advancement.
  来自SA
• Human acts have repercussions far beyond the frontiers of the human world.
  人类行为所产生的影响远远超出人类世界的范围。
  来自《权威词典》
• They are highly interested in the frontiers of science.
  他们对于科学的新领域有浓厚的兴趣.
  
• The frontiers of treason are rarely so clearly defined.
  来自fig.
• On her western frontiers Hanover was exposed to attack from France.
  来自John Brooke