The unit says that in the film you must show, not tell. Is this always true? When might it be better to tell rather than show? Explain.

This phrase "you must show, not tell" means that there was a concept of movies that the story must be told to the audience through actions and videos instead of the author telling the story through verbal voice overs or dramatizations for the audience to understand.

The screen play should be so well written that the audience must not need any summarisation o verbal entry, instead they understand and enjoy what they have been shown.

The trend to change can take several years or decades pertaining to the choice of audience.