Active vs

It can make a sentence sound vague or less engaging (correct)

It is generally more direct than active voice

It is usually structured as subject-verb-object

It is always used when the focus is on the doer of the action

They are usually structured as subject-object-verb

They are usually structured as verb-subject-object

They are usually structured as subject-verb-object (correct)

They are usually structured as object-verb-subject

Studying has been being done by them for two hours. (correct)

He will have been working on the project for a week.

The park is being played in by the children.

The project will have been completed by him.