_____form the moon,the earth with water covering 70% of it's surface appears as a "blueball".

(Seen) from the moon,the earth with water covering 70% of its surface appears as a "blueball ,
从月球上看,其表面被覆盖着70%的水的地球就像一个“蓝色球体”.
1.这句的空应该填 seen ,表示 主语the earth 与 see 之间是被动关系.
2.it's（它是） 应该是its（它的）
3.of 与 its surface 之间是所属关系 即是“它表面的”（70%.）of 的意思是“·····的”
of its surface 是介词短语作 70%.的定语.
on 是“在.上”,不能表示所属关系哦.