A:what is this used for
B:what this is used for
C:which this is used
D:that this is used for
在禁烟运动中,林则徐主张对外商“正常贸易者,加以优待,倘有带烟发觉,立正刑诛。”材料表明林则徐( )①支持正常贸易 ②反对鸦片走私 ③反对开放口岸 ④维护民族利益
人吸气时肺的容积将增大,肺内的空气压强将 ____外部空气压强, ____将外部空气压入肺内.