Put the verb in brackets into the correct form of the past simple passive. (поставь глагол в скобках в нужную форму простого времени в пассивном залоге.)
1. the
50 years ago. (to build)
2. the letters
to paris by mistake. (to post)
3. how much water
? (to pollute)
4. the door
by a man. (to open)
1. was built
2. were posted
3. was polluted
4. was opened