The Great Wall ,to be the longest wall in the world ,runs across China like a huge dragonA saying B to say Csaid Dbeing said 为什么选C麻烦解释一下
问题描述：
The Great Wall ,to be the longest wall in the world ,runs across China like a huge dragon
A saying B to say Csaid Dbeing said 为什么选C麻烦解释一下
答
said to be 过去分词成分，修饰主语the Great Wall ，成分是主语补语。
答
主语一致,可以省略which +be