Ответ:
Формулировка задания не корректная.
Объяснение:
1. When I came the lecture had already started. 2. They went to Moscow some days ago. 3. When I came he was leaving, so we had time for a few words. 4. When we came to the airport, the plane had already landed. 5. He suddenly understood that he was travelling in the wrong direction. 6. Our teacher spoke many foreign languages. 7. Who ARE you speaking now? (здесь прошедшее время уж никак не подходит) / 8/ He is playing tennis. ( аналогично. вопрос в Present Simple. ответ предполагает что Боб делает в то время как о нем спрашивают). 9. I was going home when we met. 10/ Listen, my son IS playing the piano. (мы привлекаем чье-то внимание. Глупо сказать "Послушай, мой сын играл на пианино". ) 11. They had already translated this text last lesson. 12. You will do this exercise next week. 13/ We will be discussing your plan tomorrow at 10. 14. It was raining when I went for a walk. 15. What are (were) you doing here? 16. I'm not writing at the moment.