Forgo = to give up, do without
Forego = to go before
As strange as it might sound, the past tense and past participles of these words are forwent/forgone and forewent/foregone.
...He forwent his chance to make a difference on that issue.
...Had you already forgone your chance to accompany him?
...It was a foregone conclusion.
Happy punctuating!
Margie