1. The mechanic checks the car engines every week.
\(\rightarrow\) The car engines are checked by the mechanic every week.
2. You mustn't use the machane for over 12 hours a day.
\(\rightarrow\) The machane mustn't be use for over 12 hours a day by you.
3. Linda types the reports in this office.
\(\rightarrow\) The reports are typed in this office by Linda.
XONG !!!