from the top the Olympic stadium in Beijing looks just like a birds nest made of tr

问题补充：

from the top, the Olympic stadium in Beijing looks just like a birds nest made of tree branches.

A. To see

B. See

C. Seeing

D. Seen

答案：

A. To see

B. See

C. Seeing

(答案→)D. Seen

解析：考查非谓语动词。stadium和see是被动关系,用过去分词。