帮忙选一下，并解释一下涉及的语法问题

17) ____ three times in a row, the boxer decide to give up fighting. 　　 A)shavingsdefeated B) To have defeate 　 　C)having been defeated D) To have been defeated

热心网友

17) ____ three times in a row, the boxer decide to give up fighting. 　　 A)shavingsdefeated B) To have defeate 　 　C)having been defeated D) To have been defeated 答案为 C,句子的意思是：这位拳击手被击败三次后，决定放弃比赛。此题考察的是现在分词的完成被动式做原因状语。拳击手和击败是被动关系，且“被击败”这一动作发生在“放弃”前，故选 C.

热心网友

C)having been defeated

热心网友

D) 首先确定是在一个回合里被打了三次 所以用被动语态，应该是完成形式……