In the following question, a sentence is given in the Active voice: “I saw him leaving the movie theatre.” Choose the option that best expresses this idea in the Passive voice.

Introduction / Context:
Voice transformation questions check whether a learner can express the same idea in both active and passive structures without changing the meaning or tense. The given sentence “I saw him leaving the movie theatre” is in the active voice, with “I” as the subject and “him” as the object. We must convert it into a grammatically correct passive construction while preserving the sense that the seeing happened in the past and that he was in the process of leaving.

Given Data / Assumptions:
- Active sentence: “I saw him leaving the movie theatre.”
- Subject: I
- Object: him (who was leaving the theatre).
- Verb phrase: saw (past tense) plus a participial phrase “him leaving the movie theatre”.
- We assume the tense (simple past) and the idea of continuous action (leaving) must be retained in the passive version.

Concept / Approach:
To convert from active to passive, the object of the active sentence becomes the subject of the passive sentence. The main verb is changed into an appropriate passive form of “be” plus past participle, and the original subject is introduced with “by” if needed. When a verb of perception like “see” is followed by an object and a present participle (leaving), the passive structure usually becomes: “He was seen doing something by me.”

Step-by-Step Solution:
Step 1: Identify the object in the active sentence. The person being seen is “him”. This will become the subject in the passive sentence as “He”. Step 2: Retain the tense of the verb “saw”. Simple past active (“saw”) corresponds to “was seen” in the passive. Step 3: Keep the participial phrase “leaving the movie theatre” unchanged, because it describes his ongoing action at the time. Step 4: Place the original subject “I” at the end of the sentence with the preposition “by”, giving “by me”. Step 5: Combine these elements to form: “He was seen leaving the movie theatre by me.” Step 6: Compare with the choices and note that option A matches this structure exactly, so it is correct.

Verification / Alternative check:
Check each other option carefully:
- Option B (“Leaving the movie theatre he was seen by me”) is grammatically possible but stylistically awkward and slightly changes the focus, putting the participial phrase first without necessity.
- Option C (“He was seen to be leaving the movie theatre”) uses “to be leaving”, which is not the standard transformation used in exam patterns for this structure.
- Option D (“He had been seen...”) changes the tense from simple past to past perfect, which alters the time reference.
- Option E (“He was leaving the movie theatre when I saw him”) rewrites the sentence as a complex one but is not a passive form of the original.

Why Other Options Are Wrong:
They either change the tense, disturb the emphasis, or fail to be a direct passive equivalent of the given active sentence. For full marks, the candidate must preserve tense, meaning, and focus as closely as possible.

Common Pitfalls:
Candidates sometimes mistakenly change the tense when moving into passive voice or introduce unnecessary infinitive structures like “to be leaving”. Another common error is to produce a grammatically acceptable sentence that is not strictly a passive transformation of the original. In exams, the safest option is usually the one that mirrors the original structure most closely while keeping subject and object positions correctly swapped.

Final Answer:
The best passive form of the sentence is “He was seen leaving the movie theatre by me.”