câu bị động

Mary types letters in the office.

Science and technology have completely changed human life.

My students will bring the children home.

The boys broke the window and took away some pictures.

Mary is cutting a cake with a sharp knife.

You mustn’t use this machine after 5:30 p.m.

After class, one of the students always erases the chalk board.

Will you invite her to your wedding party?

Have they changed the window of the laboratory?

Is she making big cakes for the party?