Not until he left his home _____ to know how important the family was for him.

A．did he begin

B．had he begun

C．he began

D．he has begun

霉酚酸（Mycophenolic acid)是一种生物活性化合物。下列有关霉酚酸说法不正确的是

A．分子式为：C₁₇H₂₀O₆

B．该物质能发生加成、取代、加聚等反应

C．该物质能与FeCl₃溶液发生显色反应

D．一定条件下，1 mol霉酚酸最多可与2 mol NaOH反应