chemical fit化学配合chemicaladj.化学的n.药品；化学物chemical sedimentation化学沉积chemical cxygen demand化学需氧量chemical terror attack化学恐怖袭击Chemical constituments化学成分chemical contact agent化学接触剂chemical sand-fixing化学固沙chemical caries remove化学机械除腐chemical preservatives化学防腐剂Chemical consitituents化学成分Chemical industry item化工项目