Question :
Find out the part which contains an error of subject-verb agreement:
A few steps beyond that line was seen two boxes which were black and white in colour.
Option 1: A few steps beyond
Option 2: that line was seen two boxes
Option 3: which were black
Option 4: No error
Option 5: and white in colour
Correct Answer: that line was seen two boxes
Solution :
Boxes are two, hence, ‘were’ to be used instead of ‘was’.