单选题 ______ from space, our earth, with water covering 70% of its surface, appears as a "blue planet".
A. See B. Seeing C. Seen D. To be seen

【正确答案】 C
【答案解析】[解析] 这是(过去)分词短语作状语，表示时间或条件，意思相当于when/if(it is)seen from space。