1. They (walk) in the park for two hours already.
2. Kate and Henry (walk) in the park for two hours, when it began to snow.
3. Polly and Frank (just/walk) in the city centre.
4. Dora (already/cook) dinner.
5. Emma (cook) dinner for some minutes already.
6. Kelly (cook) dinner for some minutes already when the light went out.
7. After Julia (eat) some cakes, she (order) an ice-cream and a glass of lemonade.
d) had been eating,
had ordered
8. When Mason (eat) some cakes, he (upset) his cup with coffee.
9. Frank (work) at his project for some hours when his wife phoned him.
10. David (work) at his article for some hours already.
11. Before his dad (finish) his picture, he (add) some bright colours to the flowers in the left corner.
12. Michael (build) his house in 1998.
13. The workers are very tired because they (build) this hospital for eight months without holidays.
14. After she (choose) a book, she (come up) to the librarian.
15. While Phil (choose) a poem, he (look through) all the old books.
a) was choosing,
was looking through
b) was choosing,
looked through
c) chose, looked through
d) was choosing,
had been looking through