When I got to the cinema, the film _____ for five minutes.[ ]

A: had started

B: had been on

C: has been on

D: has started

下列生物碱中，不易与大多数生物碱沉淀试剂反应生成沉淀的是（）

A.烟碱

B.秋水仙碱

C.麻黄碱和伪麻黄碱

D.莨菪碱和东莨菪碱

E.苦参碱和氧化苦参碱