=>
41. Our teeth should be cleaned twice a day.
-> bị động should be V3/ed
42. The English grammar has been explained by our teachers.
-> bị động HTHT have/has been V3/ed
43. The accident was caused in this city by some drunk drivers.
-> bị động QKĐ was/were V3/ed
44. Tom's parents will be visited next month.
-> bị động will be V3/ed
45. The secretary wasn't phoned by the manager this morning.
-> bị động QKĐ was/were (not) V3/ed
46. Was this beautful dress bought by Mary? (thiếu động từ sau Mary)
-> bị động QKĐ Was/were S V3/ed?
47. These old pictures won't be hung in the living room.
-> bị động will/won't be V3/ed
48. This factory wasn't built by the German during the Second World War.
-> bị động QKĐ was/were (not) V3/ed
49. This house and these cars are going to be painted for Christmas by the Greens.
-> bị động is/am/are going to be V3/ed

41. Our teeth should be cleaned twice a day.

- Câu bị động với động từ khiếm khuyết: S + should + be + V (Pii) + (by O).

42. The English grammar has been explained by our teachers.

- Câu bị động thì hiện tại hoàn thành: S + have/ has + been + V (Pii) + (by O).

43. The accident was caused in this city by some drunk drivers.

- Câu bị động thì quá khứ đơn: S + was/ were + V (Pii) + (by O).

44. Tom's parents will be visited next month.

- Câu bị động thì tương lai đơn: S + will + be + V (Pii) + (by O).

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

- Câu bị động thì quá khứ đơn: S + was/ were + V (Pii) + (by O).

46. Thiếu đề nên mình bỏ, không dám đoán bừa.

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

- Câu bị động thì tương lai đơn: S + will + (not) + be + V (Pii) + (by O).

48. This factory wasn't built by the German during the Second World War.

- Câu bị động thì quá khứ đơn: S + was/ were + V (Pii) + (by O).

49. This house and these cars are going to be painted for Christmas by the Greens.

- Câu bị động thì tương lai gần: S + am/ is/ are + going to + be + V (Pii) + (by O).