(2/2)ing C having seen D to have seen 这个题为什么选择B.求详解.

(2/2)ing C having seen D to have seen 这个题为什么选择B.求详解.
(2/2)ing C having seen D to have seen 这个题为什么选择B.求详解.

(2/2)ing C having seen D to have seen 这个题为什么选择B.求详解.
你的题目是什么啊

原句的意思是“看到火车已开走，（我发现）等待已无意义。”
see对于主语我（在这句话里，主语I省略了）来说是主动的，所以要用-ing形式。
整句话为：Seeing that the train is gone,it is useless to wait.