Some important voice change For HSLC exam.
1) I know him. 
-He is known to me.
2) Post the letter. 
- Let the letter be posted.
3) People call him mahatma. 
- He is called mahatma.
4) My pocket has been picked. 
- Someone has picked my pocket.
5) Duty must be done. 
- One must do one's duty.
6) He was elected president. 
- They elected him president.
7)  Who discovered America? 
- By whom was America discovered.
8) His conduct surprised us. 
- We were surprised at his conduct.
9) Someone has stolen my book. 
- My book has been stolen.
10) Change the voice. 
- Let the voice be changed.