Make the sentences passive

Somebody has wiped the dust.

The dust [ ][ ][ ].

1. We didn't expect that Sam was recording our conversation.
   We didn't expect that our conversation [ ][ ][ ].
2. Somebody is discussing a situation at the moment.
   The situation [ ][ ][ ] at the moment.
3. They have worked out a strategy.
   The strategy [ ][ ][ ][ ].
4. We have built a new circus near the city centre.
   A new circus [ ][ ][ ] near the city center.
5. When they got to the concert hall, they found that they had cancelled the show.
   When they got to the concert hall, they found that the show [ ][ ][ ].
6. They are building a new district not far from the town.
   A new ring district [ ][ ][ ] not far from the town.