The document discusses the future perfect and conditional perfect tenses.
1) The future perfect (will have + past participle) expresses an action that will be completed before a certain time in the future.
2) The conditional perfect (would have + past participle) expresses an action that would have occurred but did not, and is used to talk about imaginary or hypothetical situations in the past.
3) Both tenses are formed using a conditional auxiliary (will/would) plus have and the past participle of the verb.
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