【错误表达】

They were ignorant for the hidden dangers.

【讲解辨析】

释义：他们不知道潜伏的危险。

辨析：be ignorant of 是对......不了解，不知道，其介词不能换为for。

【正确表达】

They were ignorant of the hidden dangers.

【举一反三】

Most of us are ignorant of value of health.

我们大多数人不了解健康的可贵。