[plt-scheme] Please help : How do i add contents from user to a user defined list

Hi Guys,

I am trying to add content into a user-defined list within a loop, but
no matter what i try it is not working. Please help. Any help provided
will be greatly appericiated


(define Grades(list)); TotalAU is a list that stores all the AU
according to module

(display "Please enter the number of module taken in the semester: ")
  (newline)
  (let ((Modules(read)))
(do ((i 0 (+ i 1)))
      ((= i Modules) )
      ; User will enter all his grades
      ; Need to store into the list Grades
      (display "Please enter your grade: ")
      (newline)
      (Grade(read))
      ;Need help to proceed after this
     )