请问这里的as作为何成分？

In spite of the considerable work as China has done in its campaign to control smoking and use of tobacco, the situation of smoking control still remains grim.

as这里是关系代词，在定语从句里面指代的是the considerable work，所以它在定语从句里面应该做宾语吗？

as China has done in its campaign to control smoking and use of tobacco 

这里as有比较意义，就像。。。那样，所以这是比较分句作名词修饰语。as并非关系代词。假如把as改为that，则that为关系代词，引导定语从句。此时就没比较意义了。

不过传统语法或许会把as讲解为准关系代词，引导定语从句。假如你没学过现代语法，就如此理解也可以。