Контрольные задания

Вопрос:

Фото задания: 12. As soon as I (to see) him, I (to understand) that he (to work) hard. He (to write) something and (not to notice) anything.

Фото задания

12. As soon as I (to see) him, I (to understand) that he (to work) hard. He (to write) something and (not to notice) anything.

saw, understood, was working, was writing, did not notice