from space the earth looks like a blue ball.A. To seeB. SeeingC. SeeD. Seen

问题补充：

from space, the earth looks like a blue ball.

A. To see

B. Seeing

C. See

D. Seen

答案：

A. To see

B. Seeing

C. See

(答案→)D. Seen

解析：本题考查非费用动词。句子主语是地球而不是人，故用过去分词seen。句意：从太空看，地球看起来像一个蓝色的球。