`Answer:`

`1.` This flower is watered by my father every morning.

`2.` Fiona was invited to his birthday party by John last night.

`3.` The White House has been visited by Hundreds of people.

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

`5.` The English grammar has been explanied by our teachers.

`6.` The accidents were caused in this city by some drunk drivers.

`7.` His parents will be visited by Tom next month.

`8.` The secretary wasn't phoned by the manager this morning.

`9.` Was this beautiful drees bought by Mary?

`10.` These old pictures won't be hung in the living room.

`->` Cấu trúc câu bị động:

`-` thì Hiện tại đơn: S + am/is/are + Ved/V3 + (BY  O)

`-` thì Tương lai đơn: S + will + be + Ved/V3 + (BY  O)

`-` thì Quá khứ đơn: S + was/were + Ved/V3 + (BY  O)

`-` thì Hiện tại hoàn thành: S + have/has + been + Ved/V3 + (BY  O)

`-`Động từ khuyết thiếu: S + ĐTKT + be + Ved/V3 + (BY  O)

`1.` This flower is watered by my father every morning.

- Bị động HTĐ (+) S + am/is/are + V3/Ved + (by O)

- "This flower" là S số ít -> đi với tobe "is"

- water - watered - watered

`2.` Fiona was invited to John’s birthday party last night.

- Bị động QKĐ (+) S + was/were + V3/Ved + (by O)

- "Fiona" là S số ít -> đi với tobe "was"

- invite - invited - invited

`3.` The White House is visited by hundreds of people every day.

- Bị động HTĐ (+) S + am/is/are + V3/Ved + (by O)

- "The White House" là S số ít -> đi với tobe "is"

- visit - visited - visited

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

- Bị động MV (+) S + should + be + V3/Ved + (by O)

- clean - cleaned - cleaned

`5.` The English grammar has been explained by our teachers.

- Bị động HTHT (+) S + have/has + V3/Ved + (by O)

- "The English grammar" là S số ít -> đi với "has"

- explain - explained - explained

`6.` The accidents were caused in this city by some drunk drivers.

- Bị động QKĐ (+) S + was/were + V3/Ved + (by O)

- "The accidents" là S số nhiều -> đi với tobe were

- cause - caused - caused 

`7.` His parents will be visited by Tom next month.

- Bị động TLĐ (+) S + will be + V3/Ved + (by O)

- visit - visited - visited

`8.` The secretary wasn't phoned by the manager this morning. 

- Bị động QKĐ (-) S + wasn't/ weren't + V3/Ved + (by O)

- "The secretary" là S số ít -> đi với tobe "was"

- phone - phoned - phoned

`9.` Was this beautiful dress bought by Mary? 

- Bị động QKĐ (?) Was/Were + S + V3/Ved + .. (by O) ?

- "this beautiful dress" là S số ít -> đi với tobe "was"

- buy - bought - bought

`10.` These old pictures won't be hung in the living room.

- Bị động TLĐ (-) S + won't be + V3/Ved + (by O)

- hang - hung - hung

`@Love`