Question

As is known to all,the moon travels around the earth once every month.

Answer 1

As
is
known
to
all,the
moon
travels
around
the
earth
once
every
month.
像所有人都知道的那样，月亮每月绕地球转一次。
这个句子里，后面的[the
moon
travels
around
the
earth
once
every
month]是主句，而前面的是从句。
换成it的话应该是把句型换掉了……你是指这样的句子吗？
It
is
known
to
all
that
the
moon
travels
around
the
earth
once
every
month.
这里的It是形式主语，真正的主语是[the
moon
travels
around
the
earth
once
every
month.]
改过后的句子的正常顺序是这样的：
The
moon
travels
around
the
earth
once
every
month
is
known
to
all.
为了避免头重脚轻才使用it作为形式主语。