1. My sister gave me a new pair of jeans on my fìteenth birthday.
-> I was given a new pair of jeans by my sister on my fìteenth birthday.
-> A new pair of jeans was given to me by my sister on my fìteenth birthday.
2. The workers are building a supermarket on our street. 
-> A supermarket is being built on our street by the workers .
3. The zoo keepers feed the animals twice a day.
-> The animals are fed twice a day by the zoo keepers.
4. They have sold their car to pay their debt.
-> Their car has been sold (by them) to pay their debt.
5. We are going to grow flowers in the front garden.
-> Flowers are going to be grown in the front garden by us.
6. You mustn't use this machine after 5.30 pm.
->This machine mustn't be used (by you) after 5.30 pm .
7. My grandmother is knitting a new sweater for me.
-> I am being knitted/knit a new sweater by my grandmother.
-> A new sweater is being knitted/knit for me by my grandmother.
8. Did people make jeans two hundred years ago?
-> Were jeans made two hundred years ago?
9. We don't use this kind of cloth to make shirts.
-> This kind of cloth isn't used to make shirts by us.
10. Vietnamese woman continue to wear the unique and fashionable ao dai.
-> The unique and fashionable ao dai is continued to wear by Vietnamese woman.