Change the following sentences into passive voice :

1. 

-> Letters is typed by Mary in the office.

2.

-> You will be helped by his father tomorrow.

3.

-> Human life has been changed by science and technology.

4.

-> This bottle was broken by Peter.

5.

-> My mind can't be changed.

Cách giải :

Bị động ở thì HT :

O + be V3/ed + ( by S ) 

Bị động ở thì QK

O + was/were + V3/ed + ( by S )

`1` Letters are typed by Mary in the office

`->` Bị động - hiện tại đơn

`+` S + is/am/are + PII (by........)

`2` You will be helped by his father tomorrow 

`->` Bị động - tương lai đơn

`+` S + will be + PII (by.......)

`3` Human life has been changed by science and technlogy

`->` Bị động - hiện tại hoàn thành

`+` S + has/have + been + PII (by......)

`4` This bottle was broken by Peter 

`->` Bị động - quá khứ đơn

`+` S + was/were + PII (by....)

`5` My mind can't be changed

`->` Nothing - mang nghĩa phủ định

`->` Bị động - V khuyết thiếu

`-` S + can not + be + PII (by.........)