Hola Inma,
1. "hacen diferentes actividades [como]" ...The translation offered was "different activities such as ....": I wrote tal como for "such as" and was marked incorrect. My dictionary gives tal como as "such as / for instance" and this seems to be correct for the sentence. My dictionary gives como as "such as" as well, but with the meaning "similar to." Would a better translation have been "different activities like ......."?
2. This is about the use of "preocuparse de." The translation offered is "since they look after them at all times." I understood that the use of " preocuparse de" indicates that you worry about something in the way of occupying your mind / concerning yourself, while "preocuparse por" indicates that you may be worried about something or someone. The more research I do on this the more confusing it becomes because "ocuparse de" also seems to mean look after someone, and that seems to be closer to the translation. Either way my suggestion of preocuparse por was marked incorrect.
It would be great to have some guidance on this.
Saludos. John