短語詞組短語urea methanal 尿甲醛methanal preparation 甲醛制備methanal absorbent solution 甲醛吸收液methanal sodium bisulfite 甲醛次硫酸氫鈉hypothermia methanal steam 低溫蒸汽甲醛urea methanal preparation 尿甲醛制備methanal plus potassium permanganate fumigating 甲醛熏蒸法Tetramethyl -p-methanal 對二甲氨基甲醛 返回 methanal