Once ____,this power station will supply all the neighboring towns and villages with electricity

题目

Once ____,this power station will supply all the neighboring towns and villages with electricity
A.it being completed B,it completed C.completed D.it completing
为什么选C而不选B呢?

答案

他们都解答的不够准确.不用it是因为没有必要.你见过having做前置状语的句子吧?比如talking with Anne,he walked into the officie.（他一边和Annie说话,一边走进办公室） 为什么前面不用He呢?就是因为前后的逻辑主语...