Used to be as we are (4)
I believe the answer is:
were
I believe this clue is a double definition.
'used to be' is the first definition.
(eg 'you were...' means 'you used to be...')
'we are' is the second definition.
(contraction of 'we are')
'as' acts as a link.
(Other definitions for were that I've seen before include "Used to be" , "SECOND PART OF 9" , "Lycanthrope" , "(We/you) existed" , "SECOND PART OF 14" .)