____________ the classroom, he found all the pupils sitting at their desks and revising their homework.
Помогите, хочу разобраться. К какому разделу грамматики относится? правильный ответ, и почему остальные не подходят.

Вы хотели написать «предлоги», полагаю

Это тема "Самостоятельный причастный оборот"

Participle clauses can be formed with the present participle (-ing form of the verb) or past participle (third form of the verb). Participle clauses with past participles have a passive meaning: Having come

In the classroom это тема артикли

Having come into the classroom, he found all the pupils sitting at their desks and revising their homework.