Referee Mike Dean and assistant referee Andy Williams reported to the FA that, in their view, a number of players had surrounded Williams in an aggressive manner.
The FIFA adds and edits the responsibility of the assistant referee in the rules again and again in order to meet the need of the football match.
If the assistant referee is on the line, he can see whether the ball is over the line.
In order to reduce mistakes, the referee and the assistant referee makes strict division and cooperates tacitly.
The assistant referee should enhance the ability of offside sanctions through strengthening the ability of choosing position, improving psychological quality and enhancing resolution.
No Chinese referee was placed on the 11-person referee list, with only Mu Yuxin appointed as an assistant referee.
