At C2 you wield the passive as an instrument of academic and professional register: hiding the agent, focusing on processes, and chaining passive structures.
Agentless passive
The data were collected over six months. (no "by us")
Passive + reporting + perfect inf
He is alleged to have embezzled funds.
Causative passive
The room was made ready within the hour.
Passive of nominalised verb
A decision was reached after lengthy debate.
Why agentless passive matters in academic writing
Universalises
It has been demonstrated that... (not "we have shown")
Removes researcher
Samples were tested at three temperatures. (process focus)
Avoids "I/we"
The hypothesis was tested using a control group.
Maintains topic continuity
The findings... were analysed... were compared... (same subject throughout)
Modern academic writing increasingly accepts "we" — but in the sciences, agentless passive remains dominant for methods sections and findings.
Passive with reporting + perfect infinitive
subject + is/was + reported/alleged/believed + to have + PP ✓
Past event reported now
The suspect is believed to have fled the country.
Past at past reporting
He was thought to have left by then.
Continuous variant
She is said to have been working abroad.
Passive variant
The decision is rumoured to have been made in secret.
Double passive — passive of passive
Structure
is/are + expected/believed/required + to be + PP
Example
The contract is expected to be signed tomorrow.
Example
The new policy is intended to be applied universally.
Example
All staff are required to be trained within the first week.
Double passive carries a formal, often legalistic tone. Avoid stacking more than two passives — clarity suffers.
Passive in different tenses — comprehensive
Present simple
is/are + PP — It is recognised that...
Present continuous
is being + PP — The bridge is being repaired.
Present perfect
has been + PP — It has been demonstrated.
Past simple
was/were + PP — The data were analysed.
Past perfect
had been + PP — The decision had been made earlier.
Future
will be + PP — Results will be published.
Future perfect
will have been + PP — It will have been completed.