Question

This room has not been opened.........weeks?
1.at
2.for
3.of
4.with

Answer 1

The word "for" should go in the blanks.  The sentence should read that "The room has not been open for weeks."  The preposition "for" means "suiting for the purposes of need of."  In this case, the purpose of expressing how long the room has been closed.

Answer 2

This room has not been opened for weeks.