I believe there is a mistake with :
Les cles ont disparues
I believe this is passe compose with Avoir, so the past particle is not conjugated.
Hence Les cles ont disparu.
My French girlfriend and Google Translate concur on this.
In general I love this course. It has a few wobbly corners and some shockingly incorrect audio. But it covers a wide range of French, mostly in a sensible context. I find this much more useful than, say, learning verb infinitives with dodgy or confusing English translations. I think the approved Memrise course creators could learn from this course.
I also think that explanations of the grammar involved in each sentence would be far more useful than memes. This course covers a lot of grammar in a subtle way that may be lost on a lot of people.
I would be very happy to contribute to improving this course, if it is possible in some way. I could probably arrange some real French audio, for example.