司线员

sī xiàn yuán pàn duàn qiú shì zài jiè nèi hái shì jiè wài

司线员判断球是在界内还是界外。

A line judge shall indicate whether a shuttle is in or out.

sì míng sī xiàn yuán de zhí zé shì shén me

四名司线员的职责是什么？

What are the responsibilities of the four linesmen?