The present

The verb forms are the present, the past and the past participle.

tread, trod, trodden - nadepnąć

The present

I tread on glass every day.
Codziennie nadeptuje na szkło.

The past

I trod on a frog yesterday.
Wczoraj nadepnąłem na żabę.

The past participle

I have never trodden on a frog.
Nigdy nie nadepnąłem na żabę.