Choose the fourth word that best completes the end rhyme.box-clocks-knocks-?

Rhymes are a fun way to play with words. Many poems and song lyrics rhyme. 

The most obvious rhymes are nursery rhymes.

Example:

Hey diddle diddle
The cat and the fiddle
The cow jumped over the moon
The little dog laughed
To see such sport
And the dish ran away with the spoon