lines·man /ˈlaɪnzmən/
  常備步兵,線路保養工,邊線裁判員
  linesman
       n 1: official (in tennis or soccer or football) who assists the
            referee is some way (especially by watching for
            off-sides or out of bounds)
       2: a person who installs or repairs electrical or telephone
          lines [syn: electrician, lineman]