5. The students clean this room everyday.
$\longrightarrow$ This room is cleaned by the students everyday.
6. The workers have just built a new bridge here
$\longrightarrow$ A new bridge has been built by the workers.
7. I bought that schoolbag last year.
$\longrightarrow$ That schoolbag was bought last year by me.
8. Ba has finished these works before lunch.
$\longrightarrow$ These works has been finished before lunch by Ba
9. We will do an English test next week.
$\longrightarrow$ An English test will be done next week by us.
10. He is going to give his son a present.
$\longrightarrow$ The son is going to be given a present by his father
11. We must do the exercises carefully.
$\longrightarrow$ The exercise must be done carefully by us.