Distilled water or water treated with reverse osmosis( water captured into vapor so that all solids are left behind and then recaptured into fluid) are purer and considered safe, but are also more expensive.

• 蒸馏水或者通过反渗透处理的水（先使水转化为蒸汽以分离其中的固形物，然后再转化为水）为纯净和安全，同时价格更为昂贵。