I thank it's fun ( )on the moon A.walk B.to walkC.walking(为什么？ )

B. I think it's fun ( to walk )on the moon 句型 It's fun to do sth . 做某事有趣。

B.to walk
it's fun doing，it's fun to do都可以，但这里是fun的动词性，当有乐趣的讲，所以是it's fun to do。本回答被网友采纳