`1` My computer was used to make a presentation last week.

`2` This kind of plant was used to produce medicine.

`3` The discarded paper was used to make this flowers by the students

`4` Water colours were used to draw pictures by the students

`->` Bị động - quá khứ đơn

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

`-` S + was/were + not + PII (by........)

`?` Was/were + S + PII (by.......) ?

`->` I, she, he, it và N số ít `=>` $was$

`->` You, we, they và N số nhiều `=>` $were$

1. My computer was used to made a presentation last week.

( Bị động thì QKĐ)  S + was/were + PII (by.......)

2. This kind of plant is used to produced medicine.

( Bị động thì HTĐ)S + is/are+ PII (by.......)

3. The discarded paper is used to made this flowers by the students.

( Bị động của used to)

4. Water colours used to drew pictures by the children.

( Bị động của used to)