The forms of the infinitive 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) In the negative, not usually comes before the infinitive: I ought not to call them. I had better not call them. In some cases, the verb in the main clause is negative, not the infinitive: I want to call them. I don't want to call them. As the infinitive has no tense, it does not in itself indicate the time of the action that it refers to. However, it can have aspect, which shows the temporal relationship between the action expressed by the infinitive and the time of the preceding verb. There are four types of infinitive, each o...