Sure, here are the sentences transformed into the passive voice:

25. Is milk made by a butcher?
26. A thief was caught (by us) last night.
27. Rare meat is eaten by those wild animals.
28. Formerly, we were not lit by electricity.
29. The window was opened (by somebody).
30. He has been seen by my father.
31. We were taken to the circus by our parents yesterday.
32. He was laughed at (by us).
33. Children are taken care of by their parents.
34. This car was sold to me by my employer.
35. Our boss's question has not been answered by us.
36. She can not be trusted, she's a liar!
37. Fables are often told to us by our grandmother.
38. Coal is dug out from the earth by us.
39. Have you been forgiven by your parents?
40. We were forbidden by the policeman to play in the street.
41. These things were made by hand (by him).
42. A boa was run over by a car.
43. Work may be resumed tomorrow by the employees.
44. Lots of letters are written at Christmas and New Year.
45. The children were attracted by the acrobats and the lion-tamers.
46. Wild animals are tamed by people before they are brought to the circus.