`1.` The bicycle was bought (by her) last year.

`-` buy - bought - bought: mua

`2.` Some letters are being written (by them).

`-` write - wrote - written: viết

`3.` The dishes will have been washed by my sister by 8p.m.

`4.` The excercises had been done by the pupils.

`5.` The floor was cleaned by the children yesterday.

`6.` The letters will be sent by Nam next Sunday.

`-` send - sent - sent: gửi

`7.` The film was being watched by Daisy at 3pm yesterday.

`8.` She was bought a pen by her teacher last month.

`9.` She isn't met.

`-` meet - met - met:

`-` Nobody: Không ai (Mang nghĩa phủ định).

`10.` Dragons have never been seen.

`-` see - saw - seen: nhìn, thấy

`11.` The floor is often swept (by her) every morning.

`-` sweep - swept - swept: quét

`12.` English has to be learnt (by us) every night.

`-` learn - learned/ learnt - learned/ learnt: học

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Bị động:

`-` Thì hiện tại đơn`:` S + am/ is/ are + (not) + Vpp + (by O).

`-` Thì hiện tại tiếp diễn`:` S + am/ is/ are + (not) + being + Vpp + (by O).

`-` Thì hiện tại hoàn thành`:` S + have/ has + (not) + been + Vpp + (by O).

`-` Thì quá khứ đơn`:` S + was/ were + (not) + Vpp + (by O).

`-` Thì quá khứ tiếp diễn`:` S + was/ were + (not) + being + Vpp + (by O).

`-` Thì quá khứ hoàn thành`:` S + had + (not) + Vpp + (by O).

`-` Thì tương lai đơn`:` S + will + (not) + be + Vpp + (by O).

`-` Thì tương lai hoàn thành`:` S + will + (not) + have + been + Vpp + (by O).

`-` Động từ khuyết thiếu`:` S + modal verb + (not) + be + Vpp + (by O).