How many units must we learn this term? （改为被动语态）
How many units                            this term?
It took him two hours to finish reading the novel.（改为同义句）
He         two hours        the novel.
Parents should allow their children to choose their own clothes.(改为被动语态)
Children                             to choose their own clothes.
I was asked to clean up the room by my teacher.（改为主动语态）
My teacher                to clean up the room.
I believe that Lucy is allowed to perform a play for the old people.（改为否定句）
I       believe that Lucy                  to perform a play for the old people.