我在上刘晓燕长难句解析时她教的方法是成分对应
Under modern conditions,this requires varying measures of centralized control and hence the help of specialized scientists such as economists and operational research experts.
Varying measures 和 the help 对应起来，因为都是名词
of centralized control 和 of specialized scientists对应起来，因为都是定语
所以 AND连词前有 this requires 而连词后无成分可对应，所以连词后省略了的是this requires
完整则是and hence this requires the help of specialized scientists
Under modern conditions,this requires varying measures of centralized control and hence the help of specialized scientists such as economists and operational research experts.
Varying measures 和 the help 对应起来，因为都是名词
of centralized control 和 of specialized scientists对应起来，因为都是定语
所以 AND连词前有 this requires 而连词后无成分可对应，所以连词后省略了的是this requires
完整则是and hence this requires the help of specialized scientists
