"I don't ___ why not" (3)
I believe the answer is:
see
(Other definitions for see that I've seen before include "A bishop's district" , "Observe the bishop's domain" , "ecclesiastical division" , "Get < court < witness" , "Spot" .)
I believe the answer is:
see
(Other definitions for see that I've seen before include "A bishop's district" , "Observe the bishop's domain" , "ecclesiastical division" , "Get < court < witness" , "Spot" .)