US-P18.178ab ।US-P18.178cd ॥
In plain words
Spelling out what goes together and what drops away is only there to bring the meanings of the words back to mind. For if that recollection is missing, no one can know what the sentence means.
Close to the Sanskrit
The statement of concomitance and exclusion is but for the remembrance of the meanings of the words; in the absence of memory the meaning of the sentence cannot indeed be known by anyone.