1. He sells cars.
2. The blue car is sold.
3. In summer, more ice-cream is eaten than in winter.
4. She calls her grandparents every Friday.
5. The letters are typed/have already typed.
6. He takes his medicine every day.
7. Jane is not taken to school by her father.
8. We go to school by bus.
9. She does not work for a bank.
10. Milk is kept in the refrigerator.
Ex 2:
1.Do they teach English here ?
-> Is English taught here?

2, Will you invite her to your wedding party?
-> Will she be invited to your wedding party?

3, Has Tom finished the work?
-> Has the work been finished by TOm?

4, Did the teacher give some exercises?
-> Were some exercise given by teacher?

5, Have they changed the window of the laboratory?
-> Have the window of the laboratory been changed?

6, Is she going to write a poem?
-> Is a poem going to be written?

7, Is she making big cakes for the party?
-> Are big cake for the party being made (by she)?

8, Are the police making inquires about the thief?
-> Are the inquires about the thief being made (by the police)?

9, Must we finish the test before ten?
-> Must the test be finished before ten?

10, Will buses bring the children home?
-> Will the children be brought home (by buses)?

11, Have you finished your homework?
-> Have your homework been finished?

Ex 3: 

1, Why didn't they help him?
-> Why wasn't he helped?

2. How many games has the team played?
-> How many games have been played by the team?

3. Where do people speak E?
-> Where is english spoken ?

4. Who are they keeping in the kitchen?

-> Who is being kept in the kitchen?

5. How can they open this safe?

-> How can this safe be opened?

6. What books are people reading this year?

-> What books are being read this year?

7. How did the police find the lost man?

-> How was the lost man found by the police?

8. Who look after the childen for you?

-> Who are you looked after the children?

9. How long have they waited for the doctor?

-> How long has the doctor been waited?

10. What time can the boys hand in their papers?

-> What time can their papers be handed by the boys?

11. Who lend you this book?

-> Who are you lent this book by?

12. How many marks does the teacher give you?

-> How many marks are you given by the teacher?