Itisoftenusefultomakeacomparison.Ifyoucompare(compared不行吗？）herworkwithhis,youmayknowthedifference.Compared（comparing不行吗？主语是she,）withhiswork,assheoftensaid,shehadalongwaytogo.

Question

It is often useful to make a comparison.
If you compare(compared 不行吗？） her work with his,you may know the difference.Compared（comparing 不行吗？主语是she,） with his work,as she often said,she had a long way to go.

Answer 1

If you compare(compared 不行吗？） her work with his,you may know the difference.
这里是虚拟语气（未发生的事情），整句应该是：
If you （would） compare her work with his,you may know the difference.
would 被省略，would后边动词用原型。

Compared（comparing 不行吗？主语是she,） with his work,as she often said,she had a long way to go.
Compared（comparing 不行吗？主语是she,） with his work，
这一短语的主语不是she，按照对等原则和语义，主语应该是her work，
即：（her work was）Compared with his work，所以不能用comparing。
compare正常用法是：
compare sth with sth，
被动语态则是：sth be comared with sth
供参考