3. imagine that your classroom and the school yard have been thoroughly cleaned. say what has been done by whom. example the windows (to wash) — the windows have been washed by the girls. the desks (to wash) the flowers (to water) the floor (to mop) the furniture (to dust) the grass (to cut) the trees (to cut)

The desks have been washed by the pupils.
The flowers have been watered by the girls.
The floor has been mopped by the girls.
The furniture has been dusted by the girls.
The grass has been cut by the teachers.
The trees have been cut by the teachers.