Question

Change the following from active to passive: Someone must have tampered with the encryption keys.

• A. The encryption keys must have been tampered with.
• B. The encryption keys must have tampered by someone.
• C. The encryption keys must be tampered with by someone.
• D. The encryption keys must had been tampered with.

Answer 1

Answer:

A. The encryption keys must have been tampered with.

• The encryption keys must have been tampered with.

• Modals in past perfect active voice (must have + V3) convert to passive using must have + been + V3. The preposition with remains attached to the verb tampered.