0 any of a group of gases, such as helium and neon, that do not react with other chemicals -- 惰性气体（一系列不与其他化学物质发生反应的气体，例如氦气、氖气）
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
再长的路，一步步也能走完，再短的路，不迈开双脚也无法到达。
