years ago they knew many things about the moon.

问题描述:

years ago they knew many things about the moon.
they knew how big it was and how far it was from the earth.中的it was 放在how big ,how far

写成特殊疑问句为:How big was it?How far was it from the earth?
写成陈述语序的宾语从句为:how big it was 就是说how big其到了引导从句的作用,主语it要放在表语was的前面;而How far was it from the earth?也是同样的道理.