Cấu trúc câu bị động : S + to be + V3 +(by + O)  

* Có thể lược bỏ by O tong một số trường hợp 

   By O đứng trước trạng từ chỉ thời gian ,đứng  sau trạng từ chỉ nơi chốn

1. The watch was bought at the shop by her.

2.The house was built in 1950.

3.The exercises were done by us last week .

4.The letter were sent by pupils the day before yesterday .

5.The lesson was learned by him two weeks ago .

6.Kieu story was written by Nguyen Du .

7.The cake was made by her last night.

1. She bought the watch at the shop.

⇒ The watch was bought at the shop.

2. They built the house in 1950.

⇒ The house was built in 1950.

3. We did the exercises last week.

⇒ The exercises were done last week.

4. The pupils sent the letters the day before yesterday.

⇒ The letters were sent by the pupils the day before yesterday.

5. He learned the lessons two weeks ago.

⇒ The lessons were learned two weeks ago.

6. Nguyen Du wrote Kieu story.

⇒ Kieu story was written by Nguyen Du.

7. She made the cake last night.

⇒ The cake was made last night.

Câu bị động ở thì quá khứ đơn: S + V2/ED + O → S + was/ were + V3/ED ( by s.b)