If superlative adjectiveA part of speech that modifies, qualifies or restricts a noun or a pronoun. E.g.: The apples are ripe. ("ripe")s (especially the first, the last) are used, an infinitive structureThe way in which the parts of a sentence, clause or expression are arranged. E.g.: make somebody + infinitive in "The teacher made me rewrite the composition." can replace a defining relative clauseA group of related words containing a subject and a verb..

Geoffrey was the last to understand the joke. (= Geoffrey was the last person who understood the joke.)

If we want to express an actionA general term expressing that somebody or something does something in the passive voiceThe form of the transitive verb that shows whether the subject acts (active voice) or is acted upon (passive voice)., a passive infinitive is used:

His was the last composition to be marked. (= His was the last composition that was marked.)

Non-finite clauses replacing a relative clause
Non-finite clauses replacing a relative clause Participle clauses replacing a relative clause