A to-infinitive clause can replace a defining relative clause after ordinal numbers (the first, the second etc.), after superlatives (the best, the most beautiful etc.) and after next, last and only:
Defining and non-defining relative clauses refer to preceding nouns and are introduced by the pronouns who, whom, whose, which or that. Relative clauses usually come after the nouns that they describe:
Would rather/sooner is followed by a clause if the subject of would rather/sooner is different from the doer of the action expressed by the following verb.
