2. The dog (именно dog (собака)) is sleeping
3. Ann is swimming
4. Tony is writing a letter
5. The birds are singing
6. Mum is making a cake
Тут, насколько понимаю, требуется добавить ing.
Walking, dancing, swimming, shopping, lying, studying, laughing, writing, playing, smoking, looking, stopping, sleeping, dying, running.
3)
Не вижу примеров, но допустим:
1. Are they listening to the radio? What are they listening to?
The are not listening to the radio.
2. What is she drinking? Is she drinking Coke? She is not drinking Coke.
3. Are you dancing? Who is dancing? You are not dancing.
4. Are we playing basketball? What are we playing? We are not playing basketball.
5. Am I running? What am I doing? I am not running.