1/People should not take reference books out of the library -->Reference books....................................... 2/We should clean our teeth twice a day -->Our teeth........................................... 3/My mother has bought this bouquet of flower in the shop. -->This bouquet of flower.............................. 4/Robert Goddard invented the liquid-fueled rocket in 1962 -->The liquid-fueled rocket............................

`1.` Reference books shouldn't be taken out of the library.

`2.` Our teeth should be cleaned twice a day.

`3.` This bouquet of flower has been bought in the shop by my mother.

`4.` The liquid`-`fueled rocket was invented by Robert Goddard in `1962.`

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`@`Câu bị động:

`-` ĐTKT: S + ĐTKT + be + P2 + (by O)

`-` QKĐ: S + was/were + P2 + (by O)

`-` HTHT: S + have/has + been + P2 + (by O)

`1` Reference books should not be taken out of the library .

`-` Bị động với động từ tường thuật : S(bị động) + modal verbs + be + V3/V_ed + O ...

`2` Our teeth should be cleaned twice a day .

`-` Bị động với động từ tường thuật : S(bị động) + modal verbs + be + V3/V_ed + O ...

`3` This bouquet of flower has been bought in the shop by my mother .

`-` Bị động hiện tại hoàn thành : S(bị động) + has/have + been + V3/V_ed + O ...

`4` The liquid `-` fueled rocket was invented by Robert Goddard in 1962 .

`-` Bị động quá khứ đơn : S(bị động) + was/were + V3/V_ed + O ...