It is now being sent to his home by train.这是形式主语么?怎么理解it is

It is now being sent to his home by train ,这里being什么用法 It is now being sent to his home by train.这里的being是干嘛用的? It is now being sent to his home by train的时态问题 It is now being sent to his home by train.这句话里为什么要加being?能不能 it's now being sent to his home by train. It is now being sent to his home by train.关于这句中it is部分的时态的疑问 now the bicycle was sent to his home by train对不对?求高人详细说明 It is kilometers from my home to the train station.(同义句转换)怎么 it is being shown now. 这句这么理解?从时态语态来分析 They are sending it to his home by train.主动语态改为被动语态 改为被动语态 they are spending it to his home by train it作形式主语怎么用?it+is+adj.+to+v.