chuyển sang câu bị động 

` 16`. His homework wasn't done by him last night.

` -` Bị động QKĐ : S + was/were + V-ed/V3 + (by + O) ...

` 17`. All the questions aren't answered by the boy.

` -` Bị động HTĐ : S + is/am/are + V-ed/V3 + (by + O) ...

` 18`. Is this house repainted every year?

` -` Bị động HTĐ : S + is/am/are + V-ed/V3 + (by + O) ...

` 19`. Where was this car bought?

` -` Bị động QKĐ : S + was/were + V-ed/V3 + (by + O) ...

` 20`. America was discovered by Christopher in 1492.

` -` Bị động QKĐ : S + was/were + V-ed/V3 + (by + O) ...

`16.` His homework was not done by him last night

`17.` All the questions are not answered by the boy

`18.` Is this house repainted every year?

`19.` Where was this car bought?

`20.` America was discovered by Christopher in 1492

`______________________`

`*` Bị động HTD: S + am/is/are + V3/ed + (by + O)
`*` Bị động QKD: S + was/were + V3/ed + (by + O)