1. Peter will drive the taxi
→ The taxi will be driven by Peter
2. The teacher didn't give her exercises yesterday
-> Exercises weren't given by the teacher yesterday 
3 They don't look after the children ofter
→The children 
4. The boy can have their papers tomorrow
→ The boy's paper can be had by him tomorrow
5. Lan must send this letter to her grandma
→ This letter must be sent to Lan's grandma by her