题目

下列实验中不产生胶体的是（    ）A．分别蘸有浓氨水、浓硝酸的两支玻璃棒靠近B．打开浓盐酸的瓶口C．向盛有二硫化碳的试管中加入少量硫单质D．红磷在氯气中燃烧  答案：B解析: Though having been told to pay attention to his behavior, he performed bad ____ at the party. A. manner       B. way           C. politeness     D. manners