He said that not until the wheat died from the lack of water_____ how serious the drought was.

A．did the villagers realize

B．the villagers realized

C．the villagers did realize

D．realized the villagers

某课外活动小组利用白酒、食醋、蔗糖、淀粉等家庭厨房中常用的物质，进行有趣的化学反应原理验证。利用这些物质不能完成的实验是（    ）

A．检验自来水中是否含氯离子

B．鉴别食盐和碱面

C．蛋壳能否溶于酸

D．水壶中的水垢能否溶于酸