1. They sat/were sitting at the fire when a strange noise interrupted their calm.
2. I cannot answer you. I have not read/did not read the book yet.
3. We went/have gone to the beech every day last summer.
4. Stop! There is someone at the door and he is knocking/knocks loudly.
5. The trees grew/have grown a great deal since last spring.
6. What do you usually do/are you usually doing in your free time?
7. Where is Samantha? I think/am thinking she paints/is painting the floor in her room.
8. While mother washed/was washing dishes Elizabeth sneaked/was sneaking out.
9. We did not find/have not found the ring that Mary lost/was losing on her birthday.