Answer:
In english grammar, the Passive Voice differs from the Active Voice in the way the interest or the attention is given to the element of the sentene that experiences the action of the verb rather than the element that performs it.
To understand it better:
This Voice is generally used in the formal writting or when we do not want to explicity say <u>who performed the action</u> of the verb. As follows:
Verb TO BE correctly conjugated + main verb in past participle
However, if we want to say who performed the action (or we know it) we have to add the preposition <u>by</u>. As follows:
Verb 'to be' correctly conjugated + main verb in past participle + by+ the subject that performed the action
Knowing this, let's change the sentences:
A) Roberta <u>will take</u> Alex to the airport.
Alex <u>will be taken</u> to the airport <u>by</u> Roberta
B) The man didn't know the answer.
The answer <u>was not known</u> <u>by</u> the man
C) Nurses look after patients.
Patients <u>are looked after</u> <u>by</u> the nurses
D) Paulo Coelho wrote the book.
The book <u>was written by </u>Paulo Coelho
E) Her parents will meet Jackie.
Jackie <u>will be met by</u> her parents
