Câu bị động ( Thì QKĐ `-` TLĐ `-` ĐTKT ) :

`-` Thì QKĐ : `\text{S + was / were + V3 / PII ( by O )}`

`-` Thì TLĐ : `\text{S + will be + V3 / PII ( by O )}`

`-` ĐTKT : `\text{S + ĐTKT + be + V3 / PII ( by O )}`

`2`.A dictionary will be bought at the book store by Phong

`3`.The document must be signed by the director

`4`.I was kept waiting over an hour

`\text{@ TheFox}`

`2.` A dictionary will be bought at the book store by Phong.

`+` Cấu trúc câu bị động - thì TLĐ: S + will + be + PII + (BY  O)

`3.` The document must be signed by the director.

`+` Cấu trúc câu bị động - thì Động từ khuyết thiếu: S + ĐTKT + be + PII + (BY  O)

`4.` I was kept waiting over an hour.

`+` Cấu trúc câu bị động - thì QKĐ: S + was/were + PII + (BY  O)

`@`  Note: Khi by + O là by us, by them, by people, by someone, by somebody, by buiders, by we.....thì ta bỏ đi không sử dụng trong câu bị động.