(otukayayirunnu) ... was running
:
:2 -??????????? (umayirunnu) endings (... used to ...), for example:
::????????????? (otumayirunnu) ... used to run
:
*To form the "was doing" imperfect, take the infinitive ending in ?? (uka), for example ???? (otuka) - to run - and add the ending - ?????????? (yayirunnu).
:
*To form the "used to do" imperfect, take off the ? (ka) from the end of the "uka" form and add ?????????? (mayirunnu) in its stead.

To make a verb in the imperfect negative, add ????? (all) after