下列有关实验的叙述，正确的是

A．乙烷和氯气光照下制取纯净的氯乙烷

B．用分液漏斗分离环己烷和水的混合液体

C．用浓氨水洗涤做过银镜反应的试管

D．在苯和溴水的混合物中加入铁粉制取溴苯

PPP stands for Presentation, Practice and（）. In PPP method classes or sequences, the teacher presents the context and situation for the language, and both explains and demonstrates the meaning and form of the new language. The students then practice making sentences before going on to another stage in which they talk or write more freely.