"They know what we do not."
Translation:הם יודעים מה שאנחנו לא.
Like Remysss above, I also entered הם יודעים מה שאנחנו לא יודעים and was marked wrong. I'm wondering whether there is a subtle distinction here -- native Hebrew speakers or experts needed here please to help us out! I'm thinking Ingeborg, whose explanations are always really clear -- Could it be that my and Remyss's sentence means that they know what it is that we don't know, i.e. the object of their knowing is our areas of ignorance; whereas הם יודעים מה שאנחנו לא means that they know something and we don't know that thing, i.e. the object of their knowing is the object of our not-knowing? Like I say, it's a subtle distinction and I suspect that in ordinary speech there might be more flexibility. To me, מה שאנחנו לא without a verb after it just feels as if something is missing. I await the comments of those whose Hebrew knowledge is way ahead of mine.