Hi John, will and can are both Modal helping verbs, whose are always followed by an infinitive. A modal helping verb helps to express the modus of a (full) verb: "can forget" is NOT an abbrevation of 'be able to forget' , but "be able to" is a kind of substitute to "can". Maybe you have noticed, that the modal helping verbs are strange verbs --> no Participles and actually no past tense!
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