naturalgas天然气naturaladj.自然的；天然的；私生的natural diversity自然多样性natural astrology自然原始天文学natural wholeness自然整体natural phonation自然声natural inference自然推理natural waterfall天然瀑布natural situation自然状态natural medicines天然药物Natural essentials自然要素natural resistance自然抗病性,天然抗病性,自然抵抗力

1. Sawing with diamond abrasive tools is the most important method for the processing of natural stone.
   使用金刚石工具的锯切加工是切割天然岩石材料的最主要方式。
2. This freeze-thaw cycle, a common form of erosion of natural rocks, too, weakens a structure directly and also exposes steel reinforcing rods to water, causing them to rust.
   这种作为侵蚀天然岩石的常见形式的冻融循环，同样会直接削弱建筑物，并且还使钢筋条与水接触而导致他们生锈。