问题补充：
in thought , he almost ran into the car in front of him .
A. Losing
B. Having lost
C. Lost
D. To
答案：
A. Losing
B. Having lost
(答案→)C. Lost
D. To
解析：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。
