1. These books were sold out very quickly. (to sell out)
2. The letters were posted to Paris by mistake. (to post)
3. How much water was polluted ? (to pollute)
4. The door was opened by a man. (to open)
ОБЪЯСНЕНИЕ:
Past Simple Passive:
Сущ+was/were+ глагол с окончанием-ed/в третьей форме
Отрицательные предложения:
Сущ+ wasn’t /weren’t + глагол с окончанием-ed/в третьей форме
Вопросительные предложения:
Was/were+сущ+ глагол с -ed/в третьей форме