Hello, I'm working on a rewriting exercise so that students learn adjective gender in German. As far as I know if the adjective comes before then noun it needs an ending, but does not if it comes after the noun. So I was thinking about this type of exercise: 1. Der Film ist gut. Ja, der/er ist ein guter Film. (Is there any difference in meaning between der/er? Should I use es instead? Why?) < ... > Is it correct? Thanks so much.