This is a follow up of "Strong Verbs: Class 3", where we said:
Since German loves order, even the irregular verbs have some regularity. They sometimes follow certain patterns, so we classify them in classes. (dah!)
As seen in the previous chapter...
Class 1: ei → ie (bleiben → geblieben)
Class 2: ie → o (fliegen → geflogen)
Class 3: i → u (finden → gefunden)
Strong Verbs: CLASS 4
This group of verbs have two e's in their infinitive, just add a -ge et voilà!