bonded labour
noun /ˌbɒndɪd ˈleɪbə(r)/
  /ˌbɑːndɪd ˈleɪbər/
(US English bonded labor)
 [uncountable]- forced work for an employer for a fixed time without being paid, often as a way of paying a debt
债役劳动;抵押劳动 - Many of the immigrants are used as bonded labour.
移民中有很多人被用作债役劳工。  - Bonded labour was outlawed in the country in 1976.
该国于1976年宣布债务劳役为非法。  
 - Many of the immigrants are used as bonded labour.