。
She was furious with the children.
Literal
She [topic-は] those children [object-を] very-much got-angry.
A slightly unusual construction — 怒る ('to be/become angry') usually takes に for the target of anger (子供たちに怒った, 'got angry at the children'), but here を marks the children as direct objects. This を usage is colloquial and carries a stronger nuance: she didn't just feel anger toward them, she actively scolded or unleashed her anger on them. The を construction overlaps with 怒鳴る ('to yell at') in feel. 非常に ('very, extremely') intensifies the verb.