understand verb forms in Telugu

(nenu ardham chesukuntaanu)
I understand



(nenu ardham chesukonu)
I do not understand)



(nenu ardham chesukuntunnaanu)
I am understanding




(nenu ardham chesukuntalenu)
I am not understanding





(nenu ardham chesukunnaanu)
I understood





(nenu ardham chesukoledhu)
I did not understand