To do this, you can interweave Unity Timeline and a Dialogue System conversation.
Let's take a hypothetical scenario. The teacher will ask the viewer will be asked whether they want to go through the door on the left or the door on the right. There will need to be 4 video segments:
- Segment 1: The teacher speaks three lines to the student:
1. "There are two doors."
2. "You can choose only one."
3. "Do you want to enter the left or right door?" - Segment 2: The teacher taps his foot, waiting for the student to choose.
- Segment 3: The teacher says, "Okay, the left door." and opens the left door.
- Segment 4: The teacher says, "Very well, the right door." and opens the right door.
At appropriate times, the conversation plays timelines.
Since the first timeline has multiple subtitles, you'll not only include an action to play the Segment 1 video, but you'll also need to add "Continue Conversation" actions that progress each subtitle to the next.
Finally, set the Dialogue Manager's Subtitle Settings > Continue Button mode to Always so it waits for the Continue Conversation actions.