Hi XZ_laser,
I haven't come to a good automatic way, and only one manual work-around is to put the 
following text to the Comment of the "Input Data" node (by pressing the triangle button 
at Input Data, and select "User Comments":  Indep: %(1!col(1)[C]$) (%(1!col(1)[U]$))
  Dep: %(1!col(2)[C]$) (%(1!col(2)[U]$))
Here, it is assumed that "1" and "2" are column numbers of the independent and dependent 
variables, respectively, and the data is in the first sheet. (You should change as needed.)
Hope this makes your life easier.
--Hideo Fujii
OriginLab