154. In 1791 Robert Carter III, one of the wealthiest plantation owners in Virginia, stunned his family, friends, and neighbors by filing a deed of emancipation, setting free the more than 500 slaves who were legally considered his property.
(A) setting free the more than 500 slaves who were legally considered
(B) setting free more than the 500 slaves legally considered as
(C) and set free more than 500 slaves, who were legally considered as
(D) and set free more than the 500 slaves who were legally considered
(E) and he set free the more than 500 slaves who were legally considered as
This sentence requires that the participial phrase setting free... connect to the gerund construction by filing a deed...; it was the filing of a deed that made possible the setting free.... Choices A and B establish this connection, but only A, the best choice, completes the participial phrase appropriately. In choices B and D the misconstructed phrases set[ting] free more than the 500 slaves... mistakenly suggest that Carter set free slaves that were not his own. Choices C and D distort meaning by paralleling stunned and set free, as though these were two separate and independent actions. E begins a second independent clause, which—though grammatically acceptable—again distorts the meaning. In choices B, C, and E, considered as is unidiomatic.
在这里，逗号+setting free the more than 500 slaves who were legally considered his property.
作什么成分，是修饰stunned，作结果状语么？
如果是这样的话，则setting free…是stunned这个动作产生的结果，
可解释中说it was the filing of a deed that made possible the setting free....
怎么理解这句话，如果setting是修饰stunned这个动作的，为什么要说the filing of a deed made the setting free possible，难道setting free…与the filing of有关系么，或者说setting free是由the filing of决定的么？
请同学解答，谢谢； | 
