1. he isn't preparing the lesson now.
=> The lesson isn't being prepared now.
2. they haven't seen her friend since Tet.
=> Her friend hasn't been seen since Tet.
3. we won't help him tomorrow.
=> He won't be helped tomorrow.
4. the flowers should be watered every day.
They should water the flowers every day.
5. Tom didn't do his homework last night.
His homework wasn't done last night.
6. where did you buy these pens?
Where were these pens bought?
7. the house has been built for 2 months.
They have been building the house for 2 months.
8. I usually play soccer on Sundays
Soccer is usually played by me on Sundays.
9. her class is being cleaned now.
She is having her class cleaned now.
10. he is going to cook lunch for me.
Lunch is going to be cooked for me by him.

1. The lesson isn't being prepared now.
2. Her friend hasn't been seen since Tet.
3. He won't be helped tomorrow.
4. They should water the flowers every day.
5. His homework wasn't done last night.
6. Where were these pens bought?
7. They have been building the house for 2 months.
8. Soccer is usually played by me on Sundays.
9. She is having her class cleaned now.
10. Lunch is going to be cooked for me by him.