$I$.

$⇒$ Cấu trúc thì quá khứ đơn với động từ tobe:

(+) S + was (với danh từ số ít)/were (với danh từ số nhiều + O.

1, were

2, was

3, were

4, was

5, were

6, was

$II$.

$⇒$ Cấu trúc câu bị động thì quá khứ đơn:

(+) S + was/were + Vpp + (by O)

1, were bought

2, were cleaned

3, was eaten

4, was invented

5, were fed

6, is investigated

$III$.

$⇒$ Cấu trúc câu bị động thì quá khứ đơn (chủ động → bị động):

 S + V(past) + O $→$ S + was/were + Vpp + (by O) 

1, Mimi was given some flowers

2, Famous songs were sung by Madonna

3, Jane was offered a well-paid job

4, Ann was promised a great birthday present by her parents

5, The telephone was invented by Alexander Bell

6, Lots of beautiful pictures were taken by me

1.were

2.was

3.were

3.was

4.was

5.were

6.was

He/she/it/i+was

you/we/they+were

b2:

2.was cleaned

3.was eaten

5. was bought

4.was invented

1.were investigated

6.was felt

Câu bị động thì quá khứ đơn

Chủ động: S + V(ed/P2) + O

Bị động: S + was/were + P2

B3

1.Some flowers were given by them

2.Famous songs were sung Madonna

3.A well paid job was offered by them

4.A great birthday present was promised by Ann's parents

5.The telephone was invented by Alexander Bell

6.Lots of beautiful pictures were taken by me

Chủ ngữ là số ít ta dùng was vào câu bị động thì quá khứ đơn

Còn chủ ngữ là nhiều ta dùng were vào câu bị động thì quá khứ đơn

Chủ động: S + V(ed/P2) + O

Bị động: S + was/were + P2