1、We noticed her drinking tea in the cafe.
She was noticed drinking tea in the cafe by us.
2、They are testing the new medicine.
The new medicine is being tested by them.
3、We must keep our classroom clean.
Our classroom must be kept clean by us.
4、Will you finish your homework in an hour?
Will your homework be finished by you in an hour?
5、We should speak to old people politely.
Old people should be spoken to politely by us.