The impersonal passive, when referring to the same time as the impersonal verb

Hi, Meriem!

I would think the author wants to say that both of the two structures can be used with a subtle difference in meaning; the difference between "to be" and "to have been" in the two examples is that "To be" is used for a state or fact without reference to duration, while "to have been" is used to emphasize the duration and completion of a state.

To make it clearer, let's apply the two structures to the second example:

• B1. He was thought to have been on holiday. (emphasizes the duration and completion of the state of being on holiday, and suggests that the colleagues believed that he was on holiday at a specific time in the past and that the holiday is now over).
• B2. He was thought to be on holiday. (conveys the fact that the colleagues believed that he was on holiday, without any emphasis on duration or completion, i.e. it's less precise/detailed in conveying information).

Hello, Hussein Hassan,

Thank you for the explanation. I would like to add this thought to yours.

in B1: his colleagues had a thought that he was on holiday after his holidays had finished.

While

in B2: The colleagues had that thought, simultaneously while he was absent.

Is that right?

Here I have found a new example which has the same situation:

C. Everybody thought he did not take the prize for political reasons.
He was thought not to have taken the prize for political reasons.

the explanation: after "not taking" the price they "thought", here we emphasise that the two actions didn't happen at the same but one after the other. Even though both actions were in the past.

But, in this case, I don't think that it works to write it in the infinitive:
C1. He was thought not to take the prize for political reasons.

Do you think so?

The sentence pattern: "be thought to do something" is listed in the Macmillan dictionary. For example, Faulty wiring is thought to have caused the fire. There should not have been any problem with the sentence, "He was thought not to take the prize for political reasons."  However, it somehow sounds somewhat awkward. It is probably the word, thought, that causes the problem. The sentence "He was thought not to take the prize for political reasons" is not equivalent to " He did not take the prize for political reasons." The latter is a fact or a habit; the former is only an opinion or a belief. I suggest saying: " He was thought not likely to take the prize for political reasons.

Hey, f6pafd,

I totally agree with you. Thank you so much for your answer.