from the top of the hill the city is of round shape with a flowing river through it.A. S

问题补充：

from the top of the hill, the city is of round shape with a flowing river through it.

A. Seeing

B. To be seen

C. Seen

D. To be seeing

答案：

A. Seeing

B. To be seen

(答案→)C. Seen

D. To be seeing

解析： 考查非谓语动词，the city与see之间是动宾关系，故用过去分词，句意：这座城市从山顶上被看的话，它的形状是圆的流水流经这里。故选C。