气体 qìtǐ HSK5 gas Definitions Defs Origin Strokes Stroke Words Sentences Sents 稀有气体 xīyǒuqìtǐ noble gas any of the chemically inert gaseous elements in Group 18 of the periodic table, such as helium or neon气体扩散 qìtǐkuòsàn gaseous diffusion 温室气体 wēnshìqìtǐ greenhouse gas 生物气体 shēngwùqìtǐ biogas bio-gas