Change to Past Tense

Change the verbs in the Present Continuous Tense sentences to Past Simple Tense.
1. He is cleaning his bedroom. Last night, he his bedroom.
2. He is taking a nap. This morning, he a nap.
3. She is reading Harry Potter. Last year, she Harry Potter.
4. She is listening to some music on her iPod. Last night, she to some music on her iPod.
5. He is talking on his cellphone to his friend. Yesterday, he on his cellphone to his friend.
6. He is writing a message to his friend. This morning, he a message to his friend.
7. He is making a birthday cake. Yesterday, he a birthday cake.
8. He is inventing a car that can fly. Two years ago, he a car that can fly.
9. He is mixing powder with water. Yesterday, he powder with water.
10. The doorbell is ringing. This morning, the doorbell .