I've always understood that the phrase "two weeks" usually turns to "two weeks'" when used as a modifier -- as in "I'm giving my two weeks' notice" or "I get two weeks' vacation" ("two weeks' holiday" ...
What is the correct form when referring to the expertise of a user (e.g. in programming, writing)? user's expertise user expertise
How would you explain to a person who is learning English, and whose native language does not have attributive nouns, when the possessive should be used instead of an attributive noun? In particular, ...