keys — a small metal instrument specially cut to fit into a lock and move its bolt.
responses — an answer or reply, as in words or in some action.
acknowledgments — a section of text containing an author’s statement acknowledging his or her use of the works of other authors and thanking the people who have helped him or her, usually printed at the front of a book
cracks — to break without complete separation of parts; become fissured: The plate cracked when I dropped it, but it was still usable.
echoes — a repetition of sound produced by the reflection of sound waves from a wall, mountain, or other obstructing surface.
