Ответ:

1. We haven't already bought this dictionary. Have We already bought this dictionary?

2. He hasn't already finished his work. Has He already finished his work?

3. The cat hasn't already drunk the Milk. Has the cat already drunk the Milk?

4. They haven't already been to Canada. Have They already been to Canada?

5. I haven't already washed my car. Have l already washed my car?