被动语态

1,Cutton is grown in the south of China.
2.A new railway station has been built in our town.
3.A hospital is being built near the bank.
4.Paper was invented by Chinese.
1.If I were you,I'd buy the shoes.
2.If you had studied hard,you would have passed the exam.
3.If I were to become a bird,I would fly over the moutains.