天然

• It is a wild park .
  这是一座天然公园。
• Natural radioactivity contains a store of valuable information .
  天然放射性包含着许多有价值的信息。
• These crystals occur in nature and are the gems known as rubies .
  这些晶体是天然存在的，人们称之为红宝石。
• The method is especially attractive for gauging natural streams .
  该方法对于测量天然的流注具有特殊的吸引力。
• Naturally occurring rock oil is referred to as crude oil or petroleum .
  天然形成之石油，我们称作原油或石油。
• They sustained themselves with the spontaneous fruits of the earth .
  他们依靠大地的天然果实来维持自身的生存。
• The river formed a natural blockade to the spread of the forest fire .
  那条河成了阻止森林大火蔓延的天然屏障。
• Many natural fibers decay rapidly when exposed to aerobic cultures .
  许多天然纤维在需氧菌的侵袭下则迅速腐坏。
• Prior to treatment water may be stored in natural or artificial basins .
  处理之前，水可积蓄在天然或人工池中。