The Great Wall, to be the longest wall in the world, runs across China like a huge dragon．
A. saying
B. to say
C. said
D. being said
网友回答
A. saying
B. to say
(答案→)C. said
D. being said
解析：考查过去分词作定语。said 在这里相当于which is said,句意：在世界上被认为最长的长城横跨中国就像一条巨龙一样。故选C。