答案：C

过去分词有三个用途：（1）表示被动，如：the oppressed people ( =" the" people who are oppressed ) 被压迫的人们，又如：the exploited class ( =" the" class that is exploited ) 被剥削阶级；（2）表示完成，如：the fallen leaves ( =" the" leaves which have fallen ) 落叶，又如：an escaped prisoner ( =" a" prisoner who hads run out of prison ) 一个逃犯；（3）表示状态，如：a broken window ( =" a" window that is broken ) 一扇破窗子，又如：lost in thought陷入沉思。