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Here are the answers to complete the dialogue with "do," "does," "don't," or "doesn't":

1. A: Does Helen take the bus? B: Yes, she does.

2. A: Do I need my book? B: No, you don’t.

3. A: Does a lion eat leaves? B: No, it doesn’t.

4. A: Do you want milk? B: No, I don’t.

5. A: Do you live in a big house? B: Yes, we do.