`text{1.}` Our exercises are corrected at home by the teacher.
`text{2.}` I was given a wonderful present by Alice.
or : A wonderful present was given to me by Alice.
`text{3.}` Several new schools are being built in our town.
`text{4.}` Great progress has been made in industry, science and medicine.
`text{5.}` A lion was killed by Sam last week.
`text{6.}` Your report must be handed in before the end of this month.
* Công thức của câu bị động :
`text{+}` Hiện tại đơn : S + be + VPII + ( By O)
`text{+}` Quá khứ đơn : S + was/were + VPII + ( By O)
`text{+}` Hiện tại tiếp diễn : S + be + being + VPII + ( by O)
`text{+}` Hiện tại hoàn thành : S + have/has been + VPII + ( by O)
