This is the 16967th most frequent Russian word.
сосредоточен
Focused; concentrated.
In this sentence, 'сосредоточен' describes the state of being attentive and concentrated on a task or activity.
Он сосредоточен на своей работе.
He is focused on his work.
Here, 'сосредоточен' is used to indicate where her attention or focus is directed, in this case, towards the window.
Её взгляд был сосредоточен на окне.
Her gaze was focused on the window.
In this example, 'сосредоточены' is used to express the necessity of maintaining concentration and attention during an important event, such as an exam.