Ответ:

1) The book's title. 2) the country's economy 3) the government's decision 4) the next week's work 5) the three weeks' holiday 6) the Tom and jane's wedding 7) the K. Marx's work  8) my children's toys 9) my sister's bedroom 10) my brother-in-law's house  11) my wife's hobby 12) The Millers' car 13) her boyfriend's photo 14) the last Saturday's newspaper 15) the Professor James' umbrella