Present Active: I am on a field trip.
Present Passive: The field trip was attended by the school
Past Active: Last week the students went on a field trip.
Past Passive: The field trip had been attended by the school
Present Active: I am on a field trip.
Present Passive: The field trip was attended by the school
Past Active: Last week the students went on a field trip.
Past Passive: The field trip had been attended by the school
The present active example is good.
The past passive example is ambiguous.
Sentences where the main verb is a form of “to be” (e.g., is, am, are, was, were, be, being, been, etc.) are neither active nor passive.
present active: “I am going on a field trip.”
present passive: “The museum is being visited by the students on their field trip.”
past passive: “The museum had been visited by the students on their field trip.”