1, Someone has taken my book away
⇒ My book has been taken away by someone
2, He didn't help me with my homework
⇒ I wasn't helped with my homework by him
3, We have learnt English for three years
⇒ English has been learnt for 3 years by us
4, My father often reads books before bedtime
⇒ Books are often read before bedtime by my father
5, Lan bought some comic books for her brother
⇒ Some comic books were bought for Lan's brother by her.
6, My sister received a letter yesterday
⇒ A letter was received yesterday by my sister
7, She can solve the problem in just 2 minutes
⇒ The problem can be solved in just 2 minutes by her
8, Nowadays people use electricity for lighting
⇒ Nowadays electricity is used for lighting by people.