— ?
— She is my grandmother.
A:What does she do?
B:Who is she?
在图中,重为10牛的物体静止在水平地面上,用力的图示法画出地面受到的压力.
—No, but of all the students she did ________.
将二氧化碳通入氨水的氯化钠饱和溶液中,其化学反应方程式为:NaCl+NH3+CO2+H2O=NaHCO3↓+NH4Cl.