Change these sentences into passive 1. I'm writing her a letter. 2. They are building a big hydropower plant in Son La 3. She is writing an address on the back of the envelope

CHANGE THESE SENTENCES INTO PASSIVE
1. I'm writing her a letter
->
2. They are building a big hydropower plant in Son La
->
3. She is writing an address on the back of the envenlope
->
4. Someone has pushed the table into the corner
->
5. Somebody has bought the land next to our house
->