Here is a new exercise

For each of the following phrases, change the noun indicating possession from the plural to the singular. For example:
the owners' permission
the owner's permission

the mice's nest
the mouse's nest

1. the surgeons' skill
2. the policemen's warning
3. the directors' decision
4. the secretaries' correspondence
5. the eagles' aerie
6. the women's errand
7. the managers' assistants