It means that a candidate's score is 620 points, which is 66 points different from an admission control line or batch score line.

Fractional line difference refers to the difference between the lowest admission score line and the same batch of admission control lines, which is determined according to the situation of the school and the ranking of candidates' scores, and the lowest score line is the score of the last candidate in the school. China implements the parallel volunteer principle, and the score difference represents how many points the minimum admission score of a university exceeds the batch line.