Question

求详细解析。。

_________from space,our earth,with water covering 70% of its surface,appears as a "blue planet".
A.seen
B.seeing
C.to be seen
D.having seen

Answer 1

A 

Seen from the space, our earth appears as a "blue planet".

这里是典型的过去分词做状语，整句岁贺孙实际是下句的省略形式

When our earth  is  seen from the space, our earth appears as a "blue planet".

因为状语从句的主拍磨语跟主句的主语是一样，所以省略相乎链对不重要的分句的主语。

同时因为 be动词本身在这里没有任何意义，所以同样省略，以便整个句子简明扼要。