Выберите существительное в общем или притяжательном падеже в зависимости от смысла.
(Managers, managers') reports are very important. (These engineers, these engineers') are at the factory. We received (Jane, Jane's) letters yesterday. (Jane, Jane's) bills are not on the table. (My son, my son's) books are very interesting. Tell (Tom, Tom's) this story.

Manager's reports are very important. These engineers are at the factory. We received Jane's letters yesterday. Jane's bills are not on the table. My son's books are very interesting. Tell Tom this story.