How can I use the possessive case with many objects " s' "? 2Jane and 2Mary 2room;
it is right? :
girls’ books
Jane and Maries’ rooms
the children’s toys
the workmen’s tools
Peter and Helens’ flats are large
10Jane and 10Mary 10*room;
Jane and Maries’ rooms or/and Janes' and Maries’ rooms