Impersonal Passive – Structure with Infinitives

In the structure using infinitives, you should begin the sentence with the object of the sentence which is being reported and choose the right form of the infinitive (full or perfect). The choice of the infinitive depends on the temporal reference of the reported information:

• if the reported information refers to the present or future, use full infinitive (to + verb),
• if the reported information refers to the past, use perfect infinitive (to have + past participle)

a) People think that the summer (object) will be hot. (Present Simple of the reporting verb + future reference)

The summer is thought to be hot. (Present Simple passive of the verb “think” + full infinitive)

b) People thought that the winter (object) was mild. (Past Simple of the reporting verb + past reference)

The winter was thought to have been mild. (Past Simple passive of the verb “think” + perfect infinitive)