unpolluted [ˌʌnpəˈluːtɪd]

例句:

• I envy your peace of mind, your clean conscience, your unpolluted memory.
  我羡慕你平静的心境, 纯洁的良心和没有玷污过的记忆.
  
• Scenic , unpolluted, and prosperous: who could ask for anything more?
  风景优美, 无污染而且繁荣: 还有什么可求的 呢 ?
  
• They even sought to keep the environs clean and the drains unpolluted.
  他们还能保持环境清洁,而不污染水道.
  
• Species thrive in ponds when the water is clean and unpolluted.
  来自THETIMES
• She also warns of environmental degradation when large scale, industrial farming practices will be brought to unpolluted areas.
  来自VOA