17. Ann is in the library. She (make) a report. 18. Recently, she (plant) some bulbs and flowers. 19. I (cook) a cake when he (come back) home yesterday. 20. Now Justin (write) a book about his adventures in Tibet. I hope he can find a good publisher when it is finished.

1. Ann is in the library. She is making a report.
2. Recently, she planted some bulbs and flowers.
3. I was cooking a cake when he came back home yesterday.
4. Now Justin is writing a book about his adventures in Tibet. I hope he can find a good publisher when it is finished.

Ответ: is making; planted; was cooking, came back; is writing.