A:don’t know, were
B:hadn’t known ,are
C:haven’t known ,are
D:didn’t know, were
某品牌可乐由水、白砂糖、焦糖色素(使可乐显黑褐色)、磷酸(H3PO4)等,按一定比例混合并压入二氧化碳配制而成.某同学为了探究可乐的成分及其含量,进行如下实验.
实驗一:可乐中二氧化碳的定性检验