Does this mean "we have children who are fast and skinny" or "we have children who are fast and also children who are skinny", or is it ambiguous, like in English?
I was wondering this myself, because I put "We have fast, skinny children" and got marked wrong.
This sentence is confusing, as in Romanian "slab" can mean either skinny, weak or thin. So in this case you are not sure which English word is good.
some of the sentences used by duolingo, such as this one. You would never use in english. I think you should check if a sentence you are going to use to teach an english speaker another language actually makes sense in there native language. this is a very common problem