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

注册会计师通过对应收账款进行函证，并执行其他实质性测试的审计程序，可以对有关债权回收的可能性做出合理的结论。( )