1.
What were you ( doing) when I ( came) in? 2. When I ( came) to his house,
they (toldl) me that he (had left) an hour before. 3. On checking up
his answers he ( found) out that he (had made) several mistakes. 4. When
I (was leaving) home, the snow had already ( stopped), but a strong wind (was
blowing). 5. Are you ( reading) this book? — Yes, I (am reading) it. I ( think)
it (is) very interesting. 6. What are the children ( doing) now? — Oh,
they (are playing) the new table game which I (bought) for them the day
before yesterday. 7. They (have reached) the corner of the street by now and
(are standing) at the bus stop. 8. After we (had been walking) about two hours, we
arrived at a picturesque glade covered with fresh grass. 9. We could not go out because it (had been raining) hard since early morning.
10. She (had been teaching) at our school for twenty years now. 11. Ring me up as
soon as you (come) home. 12. He (began) to write his composition
at three o'clock. It is already eleven, and he is still ( writing) it. He
says he (will have finished) it by twelve. 13. We (have been helping) our librarian to put
the books in the right order for already three days, but we (have arranged)
only half the books.