We believe it's possibe for us______on the moon one day A.walk B.walking C.to walk D.walks为何要选A?

We believe it's possibe for us______on the moon one day A.walk B.walking C.to walk D.walks为何要选A?
We believe it's possibe for us______on the moon one day A.walk B.walking C.to walk D.walks
为何要选A?

We believe it's possibe for us______on the moon one day A.walk B.walking C.to walk D.walks为何要选A?
答案
C to walk
it is adj.for sb.to do sth