Не могу 's or s' где возможно. the birthday of her son,theatres of moscow,the decision of the government,the crew of the ship,the best museums of our city,the days of the week,work of three years,the exercise-books of the pupils,a voyage of a month,the clothes of the girls,the windows of the room,the success of the company

1.Her son's birthday.
2.Moscow's theaters.
3.The goverment's decision.
4.The ship's crew.
5.The city's best museums.
6.the week's days.
7.a the years' work.
8.the pupils' exercise books.
9.a month's voyage
10.the girls' clothes
11.the room's windows
12.the company's success