Through the feedback of assessment 1 for the first time, I have a new question.   During the filming, there are some fragments that only need to shoot the dialogue between two people.   But when we watch the movie, we will find that some clips will join the shots of other actors.   Sometimes I think about why I need to shoot this actor.   But most of the time I will ignore this problem. Because I often don’t care about this kind of problem when watching movies.  When I see this in the feedback again, I will think about it.  I found that there are some emotional expressions, plot pushes or guesses about some characters (for example, judging whether this character is a hero or a criminal in the movie).  Many hints are given from these actors who have no lines. For example, their movements, their expressions… not only can they give these hints, but they can also make some clips look richer.  For example, in a dialogue, the screen is a scene where two people talk back and forth.  This kind of clip will look boring and monotonous.  When a third person or some external factors are added, this clip instantly becomes very rich and interesting.  Some actors may not have a single line, but he can be the guide of this movie.