1. Bill will invite Ann to the party next week.
=> Ann will be invited to the party by Bill next week
2. I didn't write that letter.
=> That letter wasn't written by me
3. Hundred of people visit White House every day.
=> White Housse is visited by Hundred of people every day.
4. Everyone doesn't know this fact very well.
=> This fact isn't known very well
5. Do you wash the dishes every day ?
=> Are the dishes washed every day?
6. She bought some tulips yesterday.
=>  some tulips were bought yesterday.
7. He usually washes his car every Sunday morning.
=> his car  is usually washed every Sunday morning.
8. They cancelled all the flights because of fog.
=> all the flights  was cancelled because of fog.
9. People do not use this road very often.
=> this road isn't used very often.