def vqa_prompt(questions, n_frames):
    head = (f"These are {n_frames} frames from one video, in order. The first is the video's "
            "first frame and the last is its final frame; the rest are sampled evenly from "
            "in between.\n\n"
            f"Answer each of the following {len(questions)} questions about that video. "
            "Each is a yes/no question about what is physically visible.\n\n")
    body = "\n".join(f"{i}. {q['question']}" for i, q in enumerate(questions, 1))
    return (head + MISSING_RULE + "\n" + body +
            "\n\nReply with one line per question, in order, formatted exactly as:\n"
            "1. Yes\n2. No\n3. Missing\n(and so on). Give no other text.")