By now we have studied many grammar concepts including tense. We have seen the forms of the verb in the simple past tense is base of perfect tenses and other phrases.
We have also observed that few verbs behave differently when their past tense form is created.

As per rule, we append लो(lo) to the verb to create its past tense form for “I”.
I spoke -> मी बोललो ( mI bolalo )
I laughed -> मी हसलो ( mI hasalo )
बोल (bol)+ लो (lo) = बोललो (bolalo )
हस(has)+ लो (lo) = हसलो ( hasalo )

I went -> मी गेलो( mI gelo ).

Now verb is “जाणे”(jANe). so we should have said जा(jA) + लो(lo)= जालो (jAlo ).
But we did not say say. We appended suffix to गे(ge) to make it गेलो(gelo).

This is what I want to point out ! The unusual behavior of few verbs. !! The verbs which change themselves before creating past tense form. As past tense form is base of many other tenses and phrases it is important to know such form.

Refer below link for list of such verbs and their irregular simple past tense form.
Exceptional Verbs in Marathi which change in past tense form