chuyển các câu trên ra thể bị động giúp mih vs

21 His story isn't believed.

22 The dam may be broken by a sudden increase in water pressure.

23 Books borrowed from the library must be taken good care.

24 I was told about it by a man I know.

25 He can never be found at home for he is always on the move.

26 Milk is used for making butter and cheese.

27 Human life has completely been changed by Science and Technology.

28 My Cold used to be visited by John at weekends.

29 The river bank is covered by weeds.

30 The room was filled with smoke

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* Bị động

- Hiện tại đơn: S + am/is/are + V3/ed + (by O).

- Hiện tại hoàn thành: S + have/has + been + V3/ed + (by O). 

- Quá khứ đơn: S + was/were + V3/ed + (by O).

- Với modal verbs: S + MV + be + V3/ed + (by O).

`@Huyyy`

`@`  Bị động của các thì liên quan `:`

`-` Hiện tại đơn `:` S `+` am/is/are `+` Ved/3 `.`

`-` Quá khứ đơn `:` S `+` was/were `+` Ved/3 `.`

`-` Hiện tại hoàn thành `:` S `+` have/has `+` been `+` Ved/3 `.` 

`------------`

`21.` His story isn't believed `.`

`22.` The dam may be broken by a sudden increase in water pressure `.`

`23.` Books borrowed from the library must be taken good care `.`

`24.` I was told about it by a man I know `.`

`25.` He can never be found at home for he is always on the move `.`

`26.` Milk is used for making butter and cheese `.`

`27.` Human life has completely been changed by Science and Technology `.`

`28.` My Cold used to be visited by John at weekends `.`

`29.` The river bank is covered by weeds `.`

`30.` The room was filled with smoke `.`