高芥酸菜籽油中的游离脂肪酸主要是芥酸，此菜籽油经碱炼（氢氧化钠）后做含皂试验，称取中和油20g，用0.01212M的盐酸标准溶液0.8ml，则含皂为（）

It suddenly        to the detective that the millionaire was probably murdered by his own daughter.

A．happened

B．occurred

C．thought

D．took place