Passive voice help.me.

Solution:

1. Lots of photos were being taken by people during the race.
2. All the invitations has been sent by Mrs Jones.
3. When we walked into the sweet shop free chocolates were being given away by people. 
4. By tonight the essay must be finished by you.
5. The meeting will be probably put off by them.
6. The food will be prepared by Susan for the family dinner.