A:硝酸铵固体溶解时放热
B:石墨具有优良的导电性能,可用来做电极
C:合金硬度一般比组成它的纯金属大
D:S02、CO、NO2都是造成空气污染的气体
-Mum, can I eat ________ cakes?
-Sorry. There aren't ________ at home