2. A supermarket is being built on our street by the workers

1. I was given a new pair of jeans on my fifteenth birthday by my sister.
Hoặc: A new pair of jeans were given to me on my fifteenth birthday by my sister.
2. A supermarket is being built on our street by the workers.
3. The animals are fed twice a day by the zoo keepers.
4. Their car has been sold to pay their debt.
5. Flowers in the garden are going to be grown.
6. This button mustn't be touched while the experiment is in progress.
7. A whistle will be blown if there is an emergency .
8. Was jeans made two hundred years ago?
10. Your bill should be paid before you leve the hotel.

3. The animals are fed by the zoo keepers twice a day.

thời gian là sau by +O
nơi chốn trước by+O