If (IF) eye color were a simple single gene trait with complete dominance of brown over blue, then one third of the brown-eyed people would always have brown-eyed children if the other parent had blue eyes.
(eye color; were; a simple single gene trait with complete dominance of brown over blue) (one third of the brown-eyed people; would have; brown-eyed children; T:then; T:always) (the other parent; had; blue eyes)
eye color one third of the brown-eyed people the other parent
were would have had
a simple single gene trait with complete dominance of brown over blue
brown-eyed children T:then T:always
blue eyes