Input (grade 13): While a piece of Western music generally has a home key, a passage within it may modulate to another key, which is usually closely related to the home key, that is, close to the original around the circle of fifths.
Output (grade 10): A piece of Western music usually has a home key, and a passage within it may modulate to another key, which is usually closely related to the home key. (Usually, close to the original around the circle of fifths.)