An infinitive can be a to-infinitive or a bare infinitive (without to). There is no difference in meaning between them; some structures require a to-infinitive, while others call for a bare infinitive:
I ought to call them. (to-infinitive) I had better call them. (bare infinitive)
If we want to avoid mentioning the generalised agents we, they, people, everybody, one etc. with reporting verbs, we can use a passive reporting verb and the to-infinitive form of the verb in the reported clause.
The to-infinitive is often used in non-finite defining relative clauses after ordinal numbers (the first, the second etc.), superlatives (the best, the most beautiful etc.) and after next, last and only:
