1) People made thousand of calls from mobile phones every day.- Thousand of calls from mobile phones are made by people every day.
2) A French architect Bartholdi created the Statue of Liberty.- The Statue of Liberty was created by a French arthitect Bartholdi.
3) We will not discuss this question at the next conference.- This question won't be discussed by us at the next conference.
4) A secretary isn't writing the letter now.- The letter isn't being written by secretary now.
5) Everyone was laughing at the joke.- The joke was being laughed at by everyone.
6) Have they already prepared the presents?-Have the presents been already prepared by them?
7) She can find this book in the library.- This book can be found by her in the library.