Question

Which line is an irregular line of blank verse? “He only says, ‘Good fences make good neighbours.’” “If I could put a notion in his head:” “And on a day we meet to walk the line” “And set the wall between us once again.”

Answer 1

The line which is an irregular line of blank verse is the first one - “He only says, ‘Good fences make good neighbours.’”
A blank verse is a type of a line that consists of 10 syllables, where each second syllable is stressed ( = iambic pentameter that Shakespeare always used). The second, third, and fourth line are all good examples of blank verse, whereas the first line has 11, instead of 10 syllables. 

Answer 2

"He only says, good fences make good neighbors." Is the answer because it has 11 syllables instead of 10 like the others .