根据句意,写出所给单词的适当形式
The girl was sad. She could not make ____________ (she) understood.
Seven _____________ (twelve) of the students have taken part in the tree-planting activity since Monday.
From the _____________ (sad) on her face, we can guess something bad has happened to her.
The blue coat which is hanging on the wall must be one of the _____________ (direct) here.