Контрольные задания

Вопрос:

Фото задания: 11. Christopher goes to the university.... foot every day as he enjoys the exercise. a) by b) on c) with

Фото задания

11. Christopher goes to the university.... foot every day as he enjoys the exercise. a) by b) on c) with

Устойчивое выражение: on foot.

Ответ: b) on.