Words : Fill in the blanks with the first letter of the word given. (1)F____ is the second month of a year. (2)My favorite s____ is music. (3)Can I ask you some q____ ?(4)Come and buy your clothes at our great s____ !(5)David asks Cindy Smith about her eating h____ .
科学家在研究化学物质吋,常常对物质逬行分类,以便对同类物质的组成和性质进行深人的研究,下列4组物质:
①Ca、S、Cl2、NO2②NH3•H2O、Na2CO3、CH4、KCl③H2CO3、H2SO4、NaOH、H2SiO3④MgO、SO2、CO2、SiO2从物质的基本分类看,每组中都有一种物质与其它物质不属于同这4种物质分别是( )