Question

英语语法：（ ）from the top of the tower, the south foot of the mountain is a sea of trees.

A. Seen B. Seeing C Having seen D. To see
选什么？有什么语法知识？

Answer 1

A

这是作状语的分词短语， 逻辑主语是句子的主语 the south foot of the mountain 。
用现在分词作状语的情况：
如果句子的主语是作状语的分词短语所表动作的执行者， 用现在分词
如：
Sitting at the back of the classroom, he can't see what's on the blackboard clearly.

而如果句子的主语是作状语的分词短语所表动作的承受者， 用过去分词
如：
Seen at the top of the mountain, the school looks more beautiful.

Answer 2

答案是A
SEEN from the top of the tower(被动，分词结构) == if / when you look at the south foot（主动，状语从句） - -- - ,

Answer 3

A
被动语态
the south foot of the mountain is seen from the tower.